collectd.conf

title: collectd.conf(5)

text:
# collectd.conf(5)

## NAME
collectd.conf - Configuration for the system statistics collection daemon collectd

## SYNOPSIS

```
  BaseDir "/var/lib/collectd"
  PIDFile "/run/collectd.pid"
  Interval 10.0
  LoadPlugin cpu
  LoadPlugin load
  <LoadPlugin df>
    Interval 3600
  </LoadPlugin>
  <Plugin df>
    ValuesPercentage true
  </Plugin>
  LoadPlugin ping
  <Plugin ping>
    Host "example.org"
    Host "provider.net"
  </Plugin>
```

## DESCRIPTION
This config file controls how the system statistics collection daemon collectd behaves. The most significant option is LoadPlugin, which controls which plugins to load. These plugins ultimately define collectd's behavior. If the AutoLoadPlugin option has been enabled, the explicit LoadPlugin lines may be omitted for all plugins with a configuration block, i.e. a "<Plugin ...>" block.

The syntax of this config file is similar to the config file of the famous Apache webserver. Each line contains either an option (a key and a list of one or more values) or a section-start or -end. Empty lines and everything after a non-quoted hash-symbol ("#") are ignored. Keys are unquoted strings, consisting only of alphanumeric characters and the underscore ("_") character. Keys are handled case insensitive by collectd itself and all plugins included with it. Values can either be an unquoted string, a quoted string (enclosed in double-quotes) a number or a boolean expression. Unquoted strings consist of only alphanumeric characters and underscores ("_") and do not need to be quoted. Quoted strings are enclosed in double quotes ("""). You can use the backslash character ("\") to include double quotes as part of the string. Numbers can be specified in decimal and floating point format (using a dot "." as decimal separator), hexadecimal when using the "0x" prefix and octal with a leading zero (0). Boolean values are either true or false.

Lines may be wrapped by using "\" as the last character before the newline. This allows long lines to be split into multiple lines. Quoted strings may be wrapped as well. However, those are treated special in that whitespace at the beginning of the following lines will be ignored, which allows for nicely indenting the wrapped lines.

The configuration is read and processed in order, i.e. from top to bottom. So the plugins are loaded in the order listed in this config file. It is a good idea to load any logging plugins first in order to catch messages from plugins during configuration. Also, unless AutoLoadPlugin is enabled, the LoadPlugin option must occur before the appropriate "<Plugin ...>" block.

## GLOBAL OPTIONS
BaseDir Directory

Sets the base directory. This is the directory beneath which all RRD-files are created. Possibly more subdirectories are created. This is also the working directory for the daemon.

LoadPlugin Plugin

Loads the plugin Plugin. This is required to load plugins, unless the AutoLoadPlugin option is enabled (see below). Without any loaded plugins, collectd will be mostly useless. Only the first LoadPlugin statement or block for a given plugin name has any effect. This is useful when you want to split up the configuration into smaller files and want each file to be "self contained", i.e. it contains a Plugin block and the appropriate LoadPlugin statement. The downside is that if you have multiple conflicting LoadPlugin blocks, e.g. when they specify different intervals, only one of them (the first one encountered) will take effect and all others will be silently ignored.

LoadPlugin may either be a simple configuration statement or a block with additional options, affecting the behavior of LoadPlugin. A simple statement looks like this:

```
 LoadPlugin "cpu"

```

Options inside a LoadPlugin block can override default settings and influence the way plugins are loaded, e.g.:

```
 <LoadPlugin perl>
   Interval 60
 </LoadPlugin>

```

The following options are valid inside LoadPlugin blocks:

Globals true|false

If enabled, collectd will export all global symbols of the plugin (and of all libraries loaded as dependencies of the plugin) and, thus, makes those symbols available for resolving unresolved symbols in subsequently loaded plugins if that is supported by your system. This is useful (or possibly even required), e.g., when loading a plugin that embeds some scripting language into the daemon (e.g. the Perl and Python plugins). Scripting languages usually provide means to load extensions written in C. Those extensions require symbols provided by the interpreter, which is loaded as a dependency of the respective collectd plugin. See the documentation of those plugins (e.g., collectd-perl(5) or collectd-python(5)) for details.

By default, this is disabled. As a special exception, if the plugin name is either "perl" or "python", the default is changed to enabled in order to keep the average user from ever having to deal with this low level linking stuff.

Interval Seconds

Sets a plugin-specific interval for collecting metrics. This overrides the global Interval setting. If a plugin provides its own support for specifying an interval, that setting will take precedence.

FlushInterval Seconds

Specifies the interval, in seconds, to call the flush callback if it's defined in this plugin. By default, this is disabled.

FlushTimeout Seconds

Specifies the value of the timeout argument of the flush callback.

AutoLoadPlugin false|true

When set to false (the default), each plugin needs to be loaded explicitly, using the LoadPlugin statement documented above. If a <Plugin ...> block is encountered and no configuration handling callback for this plugin has been registered, a warning is logged and the block is ignored. When set to true, explicit LoadPlugin statements are not required. Each <Plugin ...> block acts as if it was immediately preceded by a LoadPlugin statement. LoadPlugin statements are still required for plugins that don't provide any configuration, e.g. the Load plugin.

CollectInternalStats false|true

When set to true, various statistics about the collectd daemon will be collected, with "collectd" as the plugin name. Defaults to false. The following metrics are reported:

"collectd-write_queue/queue_length"

The number of metrics currently in the write queue. You can limit the queue length with the WriteQueueLimitLow and WriteQueueLimitHigh options.

"collectd-write_queue/derive-dropped"

The number of metrics dropped due to a queue length limitation. If this value is non-zero, your system can't handle all incoming metrics and protects itself against overload by dropping metrics.

"collectd-cache/cache_size"

The number of elements in the metric cache (the cache you can interact with using collectd-unixsock(5)).

Include Path [pattern]

If Path points to a file, includes that file. If Path points to a directory, recursively includes all files within that directory and its subdirectories. If the "wordexp" function is available on your system, shell-like wildcards are expanded before files are included. This means you can use statements like the following:

```
  Include "/etc/collectd.d/*.conf"

```

Starting with version 5.3, this may also be a block in which further options affecting the behavior of Include may be specified. The following option is currently allowed:

```
  <Include "/etc/collectd.d">
    Filter "*.conf"
  </Include>

```

Filter pattern

If the "fnmatch" function is available on your system, a shell-like wildcard pattern may be specified to filter which files to include. This may be used in combination with recursively including a directory to easily be able to arbitrarily mix configuration files and other documents (e.g. README files). The given example is similar to the first example above but includes all files matching "*.conf" in any subdirectory of "/etc/collectd.d".

If more than one file is included by a single Include option, the files will be included in lexicographical order (as defined by the "strcmp" function). Thus, you can e. g. use numbered prefixes to specify the order in which the files are loaded.

To prevent loops and shooting yourself in the foot in interesting ways the nesting is limited to a depth of 8 levels, which should be sufficient for most uses. Since symlinks are followed it is still possible to crash the daemon by looping symlinks. In our opinion significant stupidity should result in an appropriate amount of pain.

It is no problem to have a block like "<Plugin foo>" in more than one file, but you cannot include files from within blocks.

PIDFile File

Sets where to write the PID file to. This file is overwritten when it exists and deleted when the program is stopped. Some init-scripts might override this setting using the -P command-line option.

PluginDir Directory

Path to the plugins (shared objects) of collectd.

TypesDB File [File ...]

Set one or more files that contain the data-set descriptions. See types.db(5) for a description of the format of this file. If this option is not specified, a default file is read. If you need to define custom types in addition to the types defined in the default file, you need to explicitly load both. In other words, if the TypesDB option is encountered the default behavior is disabled and if you need the default types you have to also explicitly load them.

Interval Seconds

Configures the interval in which to query the read plugins. Obviously smaller values lead to a higher system load produced by collectd, while higher values lead to more coarse statistics. Warning: You should set this once and then never touch it again. If you do, you will have to delete all your RRD files or know some serious RRDtool magic! (Assuming you're using the RRDtool or RRDCacheD plugin.)

MaxReadInterval Seconds

A read plugin doubles the interval between queries after each failed attempt to get data. This options limits the maximum value of the interval. The default value is 86400.

Timeout Iterations

Consider a value list "missing" when no update has been read or received for Iterations iterations. By default, collectd considers a value list missing when no update has been received for twice the update interval. Since this setting uses iterations, the maximum allowed time without update depends on the Interval information contained in each value list. This is used in the Threshold configuration to dispatch notifications about missing values, see collectd-threshold(5) for details.

ReadThreads Num

Number of threads to start for reading plugins. The default value is 5, but you may want to increase this if you have more than five plugins that take a long time to read. Mostly those are plugins that do network-IO. Setting this to a value higher than the number of registered read callbacks is not recommended.

WriteThreads Num

Number of threads to start for dispatching value lists to write plugins. The default value is 5, but you may want to increase this if you have more than five plugins that may take relatively long to write to.

WriteQueueLimitHigh HighNum

WriteQueueLimitLow LowNum

Metrics are read by the read threads and then put into a queue to be handled by the write threads. If one of the write plugins is slow (e.g. network timeouts, I/O saturation of the disk) this queue will grow. In order to avoid running into memory issues in such a case, you can limit the size of this queue. By default, there is no limit and memory may grow indefinitely. This is most likely not an issue for clients, i.e. instances that only handle the local metrics. For servers it is recommended to set this to a non-zero value, though.

You can set the limits using WriteQueueLimitHigh and WriteQueueLimitLow. Each of them takes a numerical argument which is the number of metrics in the queue. If there are HighNum metrics in the queue, any new metrics will be dropped. If there are less than LowNum metrics in the queue, all new metrics will be enqueued. If the number of metrics currently in the queue is between LowNum and HighNum, the metric is dropped with a probability that is proportional to the number of metrics in the queue (i.e. it increases linearly until it reaches 100%.)

If WriteQueueLimitHigh is set to non-zero and WriteQueueLimitLow is unset, the latter will default to half of WriteQueueLimitHigh.

If you do not want to randomly drop values when the queue size is between LowNum and HighNum, set WriteQueueLimitHigh and WriteQueueLimitLow to the same value.

Enabling the CollectInternalStats option is of great help to figure out the values to set WriteQueueLimitHigh and WriteQueueLimitLow to.

Hostname Name

Sets the hostname that identifies a host. If you omit this setting, the hostname will be determined using the gethostname(2) system call.

FQDNLookup true|false

If Hostname is determined automatically this setting controls whether or not the daemon should try to figure out the "fully qualified domain name", FQDN. This is done using a lookup of the name returned by "gethostname". This option is enabled by default.

PreCacheChain ChainName

PostCacheChain ChainName

Configure the name of the "pre-cache chain" and the "post-cache chain". Please see "FILTER CONFIGURATION" below on information on chains and how these setting change the daemon's behavior.

## PLUGIN OPTIONS
Some plugins may register own options. These options must be enclosed in a "Plugin"-Section. Which options exist depends on the plugin used. Some plugins require external configuration, too. The "apache plugin", for example, required "mod_status" to be configured in the webserver you're going to collect data from. These plugins are listed below as well, even if they don't require any configuration within collectd's configuration file.

A list of all plugins and a short summary for each plugin can be found in the README file shipped with the sourcecode and hopefully binary packets as well.

### Plugin "aggregation"
The Aggregation plugin makes it possible to aggregate several values into one using aggregation functions such as sum, average, min and max. This can be put to a wide variety of uses, e.g. average and total CPU statistics for your entire fleet.

The grouping is powerful but, as with many powerful tools, may be a bit difficult to wrap your head around. The grouping will therefore be demonstrated using an example: The average and sum of the CPU usage across all CPUs of each host is to be calculated.

To select all the affected values for our example, set "Plugin cpu" and "Type cpu". The other values are left unspecified, meaning "all values". The Host, Plugin, PluginInstance, Type and TypeInstance options work as if they were specified in the "WHERE" clause of an "SELECT" SQL statement.

```
  Plugin "cpu"
  Type "cpu"
```

Although the Host, PluginInstance (CPU number, i.e. 0, 1, 2, ...) and TypeInstance (idle, user, system, ...) fields are left unspecified in the example, the intention is to have a new value for each host / type instance pair. This is achieved by "grouping" the values using the "GroupBy" option. It can be specified multiple times to group by more than one field.

```
  GroupBy "Host"
  GroupBy "TypeInstance"
```

We do neither specify nor group by plugin instance (the CPU number), so all metrics that differ in the CPU number only will be aggregated. Each aggregation needs at least one such field, otherwise no aggregation would take place.

The full example configuration looks like this:

```
 <Plugin "aggregation">
   <Aggregation>
     Plugin "cpu"
     Type "cpu"
     GroupBy "Host"
     GroupBy "TypeInstance"
     CalculateSum true
     CalculateAverage true
   </Aggregation>
 </Plugin>
```

There are a couple of limitations you should be aware of:

- The Type cannot be left unspecified, because it is not reasonable to add apples to oranges. Also, the internal lookup structure won't work if you try to group by type.

- There must be at least one unspecified, ungrouped field. Otherwise nothing will be aggregated.

As you can see in the example above, each aggregation has its own Aggregation block. You can have multiple aggregation blocks and aggregation blocks may match the same values, i.e. one value list can update multiple aggregations. The following options are valid inside Aggregation blocks:

Host Host

Plugin Plugin

PluginInstance PluginInstance

Type Type

TypeInstance TypeInstance

Selects the value lists to be added to this aggregation. Type must be a valid data set name, see types.db(5) for details. If the string starts with and ends with a slash ("/"), the string is interpreted as a regular expression. The regex flavor used are POSIX extended regular expressions as described in regex(7). Example usage:

```
 Host "/^db[0-9]\\.example\\.com$/"

```

GroupBy Host|Plugin|PluginInstance|TypeInstance

Group valued by the specified field. The GroupBy option may be repeated to group by multiple fields.

SetHost Host

SetPlugin Plugin

SetPluginInstance PluginInstance

SetTypeInstance TypeInstance

Sets the appropriate part of the identifier to the provided string. The PluginInstance should include the placeholder "%{aggregation}" which will be replaced with the aggregation function, e.g. "average". Not including the placeholder will result in duplication warnings and/or messed up values if more than one aggregation function are enabled.

The following example calculates the average usage of all "even" CPUs:

```
 <Plugin "aggregation">
   <Aggregation>
     Plugin "cpu"
     PluginInstance "/[0,2,4,6,8]$/"
     Type "cpu"
     SetPlugin "cpu"
     SetPluginInstance "even-%{aggregation}"
     GroupBy "Host"
     GroupBy "TypeInstance"
     CalculateAverage true
   </Aggregation>
 </Plugin>

```

This will create the files:

- foo.example.com/cpu-even-average/cpu-idle

- foo.example.com/cpu-even-average/cpu-system

- foo.example.com/cpu-even-average/cpu-user

- ...

CalculateNum true|false

CalculateSum true|false

CalculateAverage true|false

CalculateMinimum true|false

CalculateMaximum true|false

CalculateStddev true|false

Boolean options for enabling calculation of the number of value lists, their sum, average, minimum, maximum and / or standard deviation. All options are disabled by default.

### Plugin "amqp"
The AMQP plugin can be used to communicate with other instances of collectd or third party applications using an AMQP 0.9.1 message broker. Values are sent to or received from the broker, which handles routing, queueing and possibly filtering out messages.

Synopsis:

```
 <Plugin "amqp">
   # Send values to an AMQP broker
   <Publish "some_name">
     Host "localhost"
     Host "fallback-amqp.example.com"
     Port "5672"
     VHost "/"
     User "guest"
     Password "guest"
     Exchange "amq.fanout"
 #   ExchangeType "fanout"
 #   RoutingKey "collectd"
 #   Persistent false
 #   ConnectionRetryDelay 0
 #   Format "command"
 #   StoreRates false
 #   TLSEnabled false
 #   TLSVerifyPeer true
 #   TLSVerifyHostName true
 #   TLSCACert "/path/to/ca.pem"
 #   TLSClientCert "/path/to/client-cert.pem"
 #   TLSClientKey "/path/to/client-key.pem"
 #   GraphitePrefix "collectd."
 #   GraphiteEscapeChar "_"
 #   GraphiteSeparateInstances false
 #   GraphiteAlwaysAppendDS false
 #   GraphitePreserveSeparator false
   </Publish>
   # Receive values from an AMQP broker
   <Subscribe "some_name">
     Host "localhost"
     Port "5672"
     VHost "/"
     User "guest"
     Password "guest"
     Exchange "amq.fanout"
 #   ExchangeType "fanout"
 #   Queue "queue_name"
 #   QueueDurable false
 #   QueueAutoDelete true
 #   RoutingKey "collectd.#"
 #   ConnectionRetryDelay 0
 #   TLSEnabled false
 #   TLSVerifyPeer true
 #   TLSVerifyHostName true
 #   TLSCACert "/path/to/ca.pem"
 #   TLSClientCert "/path/to/client-cert.pem"
 #   TLSClientKey "/path/to/client-key.pem"
   </Subscribe>
 </Plugin>
```

The plugin's configuration consists of a number of Publish and Subscribe blocks, which configure sending and receiving of values respectively. The two blocks are very similar, so unless otherwise noted, an option can be used in either block. The name given in the blocks starting tag is only used for reporting messages, but may be used to support flushing of certain Publish blocks in the future.

Host Host [Host ...]

Hostname or IP-address of the AMQP broker. Defaults to the default behavior of the underlying communications library, rabbitmq-c, which is "localhost". If multiple hosts are specified, then a random one is chosen at each (re)connection attempt. This is useful for failover with a clustered broker.

Port Port

Service name or port number on which the AMQP broker accepts connections. This argument must be a string, even if the numeric form is used. Defaults to "5672".

VHost VHost

Name of the virtual host on the AMQP broker to use. Defaults to "/".

User User

Password Password

Credentials used to authenticate to the AMQP broker. By default "guest"/"guest" is used.

Exchange Exchange

In Publish blocks, this option specifies the exchange to send values to. By default, "amq.fanout" will be used. In Subscribe blocks this option is optional. If given, a binding between the given exchange and the queue is created, using the routing key if configured. See the Queue and RoutingKey options below.

ExchangeType Type

If given, the plugin will try to create the configured exchange with this type after connecting. When in a Subscribe block, the queue will then be bound to this exchange.

Queue Queue (Subscribe only)

Configures the queue name to subscribe to. If no queue name was configured explicitly, a unique queue name will be created by the broker.

QueueDurable true|false (Subscribe only)

Defines if the queue subscribed to is durable (saved to persistent storage) or transient (will disappear if the AMQP broker is restarted). Defaults to "false". This option should be used in conjunction with the Persistent option on the publish side.

QueueAutoDelete true|false (Subscribe only)

Defines if the queue subscribed to will be deleted once the last consumer unsubscribes. Defaults to "true".

RoutingKey Key

In Publish blocks, this configures the routing key to set on all outgoing messages. If not given, the routing key will be computed from the identifier of the value. The host, plugin, type and the two instances are concatenated together using dots as the separator and all containing dots replaced with slashes. For example "collectd.host/example/com.cpu.0.cpu.user". This makes it possible to receive only specific values using a "topic" exchange. In Subscribe blocks, configures the routing key used when creating a binding between an exchange and the queue. The usual wildcards can be used to filter messages when using a "topic" exchange. If you're only interested in CPU statistics, you could use the routing key "collectd.*.cpu.#" for example.

Persistent true|false (Publish only)

Selects the delivery method to use. If set to true, the persistent mode will be used, i.e. delivery is guaranteed. If set to false (the default), the transient delivery mode will be used, i.e. messages may be lost due to high load, overflowing queues or similar issues.

ConnectionRetryDelay Delay

When the connection to the AMQP broker is lost, defines the time in seconds to wait before attempting to reconnect. Defaults to 0, which implies collectd will attempt to reconnect at each read interval (in Subscribe mode) or each time values are ready for submission (in Publish mode).

Format Command|JSON|Graphite (Publish only)

Selects the format in which messages are sent to the broker. If set to Command (the default), values are sent as "PUTVAL" commands which are identical to the syntax used by the Exec and UnixSock plugins. In this case, the "Content-Type" header field will be set to "text/collectd". If set to JSON, the values are encoded in the JavaScript Object Notation, an easy and straight forward exchange format. The "Content-Type" header field will be set to "application/json".

If set to Graphite, values are encoded in the Graphite format, which is "<metric> <value> <timestamp>\n". The "Content-Type" header field will be set to "text/graphite".

A subscribing client should use the "Content-Type" header field to determine how to decode the values. Currently, the AMQP plugin itself can only decode the Command format.

StoreRates true|false (Publish only)

Determines whether or not "COUNTER", "DERIVE" and "ABSOLUTE" data sources are converted to a rate (i.e. a "GAUGE" value). If set to false (the default), no conversion is performed. Otherwise the conversion is performed using the internal value cache. Please note that currently this option is only used if the Format option has been set to JSON.

GraphitePrefix (Publish and Format=Graphite only)

A prefix can be added in the metric name when outputting in the Graphite format. It's added before the Host name. Metric name will be "<prefix><host><postfix><plugin><type><name>"

GraphitePostfix (Publish and Format=Graphite only)

A postfix can be added in the metric name when outputting in the Graphite format. It's added after the Host name. Metric name will be "<prefix><host><postfix><plugin><type><name>"

GraphiteEscapeChar (Publish and Format=Graphite only)

Specify a character to replace dots (.) in the host part of the metric name. In Graphite metric name, dots are used as separators between different metric parts (host, plugin, type). Default is "_" (Underscore).

GraphiteSeparateInstances true|false

If set to true, the plugin instance and type instance will be in their own path component, for example "host.cpu.0.cpu.idle". If set to false (the default), the plugin and plugin instance (and likewise the type and type instance) are put into one component, for example "host.cpu-0.cpu-idle".

GraphiteAlwaysAppendDS true|false

If set to true, append the name of the Data Source (DS) to the "metric" identifier. If set to false (the default), this is only done when there is more than one DS.

GraphitePreserveSeparator false|true

If set to false (the default) the "." (dot) character is replaced with GraphiteEscapeChar. Otherwise, if set to true, the "." (dot) character is preserved, i.e. passed through.

TLSEnabled true|false

If set to true then connect to the broker using a TLS connection. If set to false (the default), then a plain text connection is used. Requires rabbitmq-c >= 0.4.

TLSVerifyPeer true|false

If set to true (the default) then the server certificate chain is verified. Setting this to false will skip verification (insecure). Requires rabbitmq-c >= 0.8.

TLSVerifyHostName true|false

If set to true (the default) then the server host name is verified. Setting this to false will skip verification (insecure). Requires rabbitmq-c >= 0.8.

TLSCACert Path

Path to the CA cert file in PEM format.

TLSClientCert Path

Path to the client certificate in PEM format. If this is set, then TLSClientKey must be set as well.

TLSClientKey Path

Path to the client key in PEM format. If this is set, then TLSClientCert must be set as well.

### Plugin "amqp1"
The AMQP1 plugin can be used to communicate with other instances of collectd or third party applications using an AMQP 1.0 message intermediary. Metric values or notifications are sent to the messaging intermediary which may handle direct messaging or queue based transfer.

Synopsis:

```
 <Plugin "amqp1">
   # Send values to an AMQP 1.0 intermediary
  <Transport "name">
    Host "localhost"
    Port "5672"
    User "guest"
    Password "guest"
    Address "collectd"
#    RetryDelay 1
    <Instance "some_name">
        Format "command"
        PreSettle false
        Notify false
 #      StoreRates false
 #      GraphitePrefix "collectd."
 #      GraphiteEscapeChar "_"
 #      GraphiteSeparateInstances false
 #      GraphiteAlwaysAppendDS false
 #      GraphitePreserveSeparator false
    </Instance>
  </Transport>
 </Plugin>
```

The plugin's configuration consists of a Transport that configures communications to the AMQP 1.0 messaging bus and one or more Instance corresponding to metric or event publishers to the messaging system.

The address in the Transport block concatenated with the name given in the Instance block starting tag will be used as the send-to address for communications over the messaging link.

The following options are accepted within each Transport block:

Host Host

Hostname or IP-address of the AMQP 1.0 intermediary. Defaults to the default behavior of the underlying communications library, libqpid-proton, which is "localhost".

Port Port

Service name or port number on which the AMQP 1.0 intermediary accepts connections. This argument must be a string, even if the numeric form is used. Defaults to "5672".

User User

Password Password

Credentials used to authenticate to the AMQP 1.0 intermediary. By default "guest"/"guest" is used.

Address Address

This option specifies the prefix for the send-to value in the message. By default, "collectd" will be used.

RetryDelay RetryDelay

When the AMQP1 connection is lost, defines the time in seconds to wait before attempting to reconnect. Defaults to 1, which implies attempt to reconnect at 1 second intervals.

SendQueueLimit SendQueueLimit If there is no AMQP1 connection, the plugin will continue to queue messages to send, which could result in unbounded memory consumption. This parameter is used to limit the number of messages in the outbound queue to the specified value. The default value is 0, which disables this feature.

The following options are accepted within each Instance block:

Format Command|JSON|Graphite

Selects the format in which messages are sent to the intermediary. If set to Command (the default), values are sent as "PUTVAL" commands which are identical to the syntax used by the Exec and UnixSock plugins. In this case, the "Content-Type" header field will be set to "text/collectd". If set to JSON, the values are encoded in the JavaScript Object Notation, an easy and straight forward exchange format. The "Content-Type" header field will be set to "application/json".

If set to Graphite, values are encoded in the Graphite format, which is "<metric> <value> <timestamp>\n". The "Content-Type" header field will be set to "text/graphite".

A subscribing client should use the "Content-Type" header field to determine how to decode the values.

PreSettle true|false

If set to false (the default), the plugin will wait for a message acknowledgement from the messaging bus before sending the next message. This indicates transfer of ownership to the messaging system. If set to true, the plugin will not wait for a message acknowledgement and the message may be dropped prior to transfer of ownership.

Notify true|false

If set to false (the default), the plugin will service the instance write call back as a value list. If set to true the plugin will service the instance as a write notification callback for alert formatting.

StoreRates true|false

Determines whether or not "COUNTER", "DERIVE" and "ABSOLUTE" data sources are converted to a rate (i.e. a "GAUGE" value). If set to false (the default), no conversion is performed. Otherwise the conversion is performed using the internal value cache. Please note that currently this option is only used if the Format option has been set to JSON.

GraphitePrefix

A prefix can be added in the metric name when outputting in the Graphite format. It's added before the Host name. Metric name will be "<prefix><host><postfix><plugin><type><name>"

GraphitePostfix

A postfix can be added in the metric name when outputting in the Graphite format. It's added after the Host name. Metric name will be "<prefix><host><postfix><plugin><type><name>"

GraphiteEscapeChar

Specify a character to replace dots (.) in the host part of the metric name. In Graphite metric name, dots are used as separators between different metric parts (host, plugin, type). Default is "_" (Underscore).

GraphiteSeparateInstances true|false

If set to true, the plugin instance and type instance will be in their own path component, for example "host.cpu.0.cpu.idle". If set to false (the default), the plugin and plugin instance (and likewise the type and type instance) are put into one component, for example "host.cpu-0.cpu-idle".

GraphiteAlwaysAppendDS true|false

If set to true, append the name of the Data Source (DS) to the "metric" identifier. If set to false (the default), this is only done when there is more than one DS.

GraphitePreserveSeparator false|true

If set to false (the default) the "." (dot) character is replaced with GraphiteEscapeChar. Otherwise, if set to true, the "." (dot) character is preserved, i.e. passed through.

### Plugin "apache"
To configure the "apache"-plugin you first need to configure the Apache webserver correctly. The Apache-plugin "mod_status" needs to be loaded and working and the "ExtendedStatus" directive needs to be enabled. You can use the following snipped to base your Apache config upon:

```
  ExtendedStatus on
  <IfModule mod_status.c>
    <Location /mod_status>
      SetHandler server-status
    </Location>
  </IfModule>
```

Since its "mod_status" module is very similar to Apache's, lighttpd is also supported. It introduces a new field, called "BusyServers", to count the number of currently connected clients. This field is also supported.

The configuration of the Apache plugin consists of one or more "<Instance />" blocks. Each block requires one string argument as the instance name. For example:

```
 <Plugin "apache">
   <Instance "www1">
     URL "http://www1.example.com/mod_status?auto"
   </Instance>
   <Instance "www2">
     URL "http://www2.example.com/mod_status?auto"
   </Instance>
 </Plugin>
```

The instance name will be used as the plugin instance. To emulate the old (version 4) behavior, you can use an empty string (""). In order for the plugin to work correctly, each instance name must be unique. This is not enforced by the plugin and it is your responsibility to ensure it.

The following options are accepted within each Instance block:

URL http://host/mod_status?auto

Sets the URL of the "mod_status" output. This needs to be the output generated by "ExtendedStatus on" and it needs to be the machine readable output generated by appending the "?auto" argument. This option is mandatory.

User Username

Optional user name needed for authentication.

Password Password

Optional password needed for authentication.

VerifyPeer true|false

Enable or disable peer SSL certificate verification. See <http://curl.haxx.se/docs/sslcerts.html> for details. Enabled by default.

VerifyHost true|false

Enable or disable peer host name verification. If enabled, the plugin checks if the "Common Name" or a "Subject Alternate Name" field of the SSL certificate matches the host name provided by the URL option. If this identity check fails, the connection is aborted. Obviously, only works when connecting to a SSL enabled server. Enabled by default.

CACert File

File that holds one or more SSL certificates. If you want to use HTTPS you will possibly need this option. What CA certificates come bundled with "libcurl" and are checked by default depends on the distribution you use.

SSLCiphers list of ciphers

Specifies which ciphers to use in the connection. The list of ciphers must specify valid ciphers. See <http://www.openssl.org/docs/apps/ciphers.html> for details.

Timeout Milliseconds

The Timeout option sets the overall timeout for HTTP requests to URL, in milliseconds. By default, the configured Interval is used to set the timeout.

### Plugin "apcups"
Host Hostname

Hostname of the host running apcupsd. Defaults to localhost. Please note that IPv6 support has been disabled unless someone can confirm or decline that apcupsd can handle it.

Port Port

TCP-Port to connect to. Defaults to 3551.

ReportSeconds true|false

If set to true, the time reported in the "timeleft" metric will be converted to seconds. This is the recommended setting. If set to false, the default for backwards compatibility, the time will be reported in minutes.

PersistentConnection true|false

The plugin is designed to keep the connection to apcupsd open between reads. If plugin poll interval is greater than 15 seconds (hardcoded socket close timeout in apcupsd NIS), then this option is false by default. You can instruct the plugin to close the connection after each read by setting this option to false or force keeping the connection by setting it to true.

If apcupsd appears to close the connection due to inactivity quite quickly, the plugin will try to detect this problem and switch to an open-read-close mode.

### Plugin "aquaero"
This plugin collects the value of the available sensors in an Aquaero 5 board. Aquaero 5 is a water-cooling controller board, manufactured by Aqua Computer GmbH <http://www.aquacomputer.de/>, with a USB2 connection for monitoring and configuration. The board can handle multiple temperature sensors, fans, water pumps and water level sensors and adjust the output settings such as fan voltage or power used by the water pump based on the available inputs using a configurable controller included in the board. This plugin collects all the available inputs as well as some of the output values chosen by this controller. The plugin is based on the libaquaero5 library provided by aquatools-ng.

Device DevicePath

Device path of the Aquaero 5's USB HID (human interface device), usually in the form "/dev/usb/hiddevX". If this option is no set the plugin will try to auto-detect the Aquaero 5 USB device based on vendor-ID and product-ID.

### Plugin "ascent"
This plugin collects information about an Ascent server, a free server for the "World of Warcraft" game. This plugin gathers the information by fetching the XML status page using "libcurl" and parses it using "libxml2".

The configuration options are the same as for the "apache" plugin above:

URL http://localhost/ascent/status/

Sets the URL of the XML status output.

User Username

Optional user name needed for authentication.

Password Password

Optional password needed for authentication.

VerifyPeer true|false

Enable or disable peer SSL certificate verification. See <http://curl.haxx.se/docs/sslcerts.html> for details. Enabled by default.

VerifyHost true|false

Enable or disable peer host name verification. If enabled, the plugin checks if the "Common Name" or a "Subject Alternate Name" field of the SSL certificate matches the host name provided by the URL option. If this identity check fails, the connection is aborted. Obviously, only works when connecting to a SSL enabled server. Enabled by default.

CACert File

File that holds one or more SSL certificates. If you want to use HTTPS you will possibly need this option. What CA certificates come bundled with "libcurl" and are checked by default depends on the distribution you use.

Timeout Milliseconds

The Timeout option sets the overall timeout for HTTP requests to URL, in milliseconds. By default, the configured Interval is used to set the timeout.

### Plugin "barometer"
This plugin reads absolute air pressure using digital barometer sensor on a I2C bus. Supported sensors are:

MPL115A2 from Freescale, see <http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MPL115A>.

MPL3115 from Freescale see <http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MPL3115A2>.

BMP085 from Bosch Sensortec

The sensor type - one of the above - is detected automatically by the plugin and indicated in the plugin_instance (you will see subdirectory "barometer-mpl115" or "barometer-mpl3115", or "barometer-bmp085"). The order of detection is BMP085 -> MPL3115 -> MPL115A2, the first one found will be used (only one sensor can be used by the plugin).

The plugin provides absolute barometric pressure, air pressure reduced to sea level (several possible approximations) and as an auxiliary value also internal sensor temperature. It uses (expects/provides) typical metric units - pressure in [hPa], temperature in [C], altitude in [m].

It was developed and tested under Linux only. The only platform dependency is the standard Linux i2c-dev interface (the particular bus driver has to support the SM Bus command subset).

The reduction or normalization to mean sea level pressure requires (depending on selected method/approximation) also altitude and reference to temperature sensor(s). When multiple temperature sensors are configured the minimum of their values is always used (expecting that the warmer ones are affected by e.g. direct sun light at that moment).

Synopsis:

```
  <Plugin "barometer">
     Device            "/dev/i2c-0";
     Oversampling      512
     PressureOffset    0.0
     TemperatureOffset 0.0
     Normalization     2
     Altitude          238.0
     TemperatureSensor "myserver/onewire-F10FCA000800/temperature"
  </Plugin>
```

Device device

The only mandatory configuration parameter. Device name of the I2C bus to which the sensor is connected. Note that typically you need to have loaded the i2c-dev module. Using i2c-tools you can check/list i2c buses available on your system by:

```
  i2cdetect -l

```

Then you can scan for devices on given bus. E.g. to scan the whole bus 0 use:

```
  i2cdetect -y -a 0

```

This way you should be able to verify that the pressure sensor (either type) is connected and detected on address 0x60.

Oversampling value

Optional parameter controlling the oversampling/accuracy. Default value is 1 providing fastest and least accurate reading. For MPL115 this is the size of the averaging window. To filter out sensor noise a simple averaging using floating window of this configurable size is used. The plugin will use average of the last "value" measurements (value of 1 means no averaging). Minimal size is 1, maximal 1024.

For MPL3115 this is the oversampling value. The actual oversampling is performed by the sensor and the higher value the higher accuracy and longer conversion time (although nothing to worry about in the collectd context). Supported values are: 1, 2, 4, 8, 16, 32, 64 and 128. Any other value is adjusted by the plugin to the closest supported one.

For BMP085 this is the oversampling value. The actual oversampling is performed by the sensor and the higher value the higher accuracy and longer conversion time (although nothing to worry about in the collectd context). Supported values are: 1, 2, 4, 8. Any other value is adjusted by the plugin to the closest supported one.

PressureOffset offset

Optional parameter for MPL3115 only. You can further calibrate the sensor by supplying pressure and/or temperature offsets. This is added to the measured/caclulated value (i.e. if the measured value is too high then use negative offset). In hPa, default is 0.0.

TemperatureOffset offset

Optional parameter for MPL3115 only. You can further calibrate the sensor by supplying pressure and/or temperature offsets. This is added to the measured/caclulated value (i.e. if the measured value is too high then use negative offset). In C, default is 0.0.

Normalization method

Optional parameter, default value is 0. Normalization method - what approximation/model is used to compute the mean sea level pressure from the air absolute pressure.

Supported values of the "method" (integer between from 0 to 2) are:

0 - no conversion, absolute pressure is simply copied over. For this method you do not need to configure "Altitude" or "TemperatureSensor".

1 - international formula for conversion , See <http://en.wikipedia.org/wiki/Atmospheric_pressure#Altitude_atmospheric_pressure_variation>. For this method you have to configure "Altitude" but do not need "TemperatureSensor" (uses fixed global temperature average instead).

2 - formula as recommended by the Deutsche Wetterdienst (German Meteorological Service). See <http://de.wikipedia.org/wiki/Barometrische_H%C3%B6henformel#Theorie> For this method you have to configure both "Altitude" and "TemperatureSensor".

Altitude altitude

The altitude (in meters) of the location where you meassure the pressure.

TemperatureSensor reference

Temperature sensor(s) which should be used as a reference when normalizing the pressure using "Normalization" method 2. When specified more sensors a minimum is found and used each time. The temperature reading directly from this pressure sensor/plugin is typically not suitable as the pressure sensor will be probably inside while we want outside temperature. The collectd reference name is something like <hostname>/<plugin_name>-<plugin_instance>/<type>-<type_instance> (<type_instance> is usually omitted when there is just single value type). Or you can figure it out from the path of the output data files.

### Plugin "battery"
The battery plugin reports the remaining capacity, power and voltage of laptop batteries.

ValuesPercentage false|true

When enabled, remaining capacity is reported as a percentage, e.g. "42% capacity remaining". Otherwise the capacity is stored as reported by the battery, most likely in "Wh". This option does not work with all input methods, in particular when only "/proc/pmu" is available on an old Linux system. Defaults to false.

ReportDegraded false|true

Typical laptop batteries degrade over time, meaning the capacity decreases with recharge cycles. The maximum charge of the previous charge cycle is tracked as "last full capacity" and used to determine that a battery is "fully charged". When this option is set to false, the default, the battery plugin will only report the remaining capacity. If the ValuesPercentage option is enabled, the relative remaining capacity is calculated as the ratio of the "remaining capacity" and the "last full capacity". This is what most tools, such as the status bar of desktop environments, also do.

When set to true, the battery plugin will report three values: charged (remaining capacity), discharged (difference between "last full capacity" and "remaining capacity") and degraded (difference between "design capacity" and "last full capacity").

QueryStateFS false|true

When set to true, the battery plugin will only read statistics related to battery performance as exposed by StateFS at /run/state. StateFS is used in Mer-based Sailfish OS, for example.

### Plugin "bind"
Starting with BIND 9.5.0, the most widely used DNS server software provides extensive statistics about queries, responses and lots of other information. The bind plugin retrieves this information that's encoded in XML and provided via HTTP and submits the values to collectd.

To use this plugin, you first need to tell BIND to make this information available. This is done with the "statistics-channels" configuration option:

```
 statistics-channels {
   inet localhost port 8053;
 };
```

The configuration follows the grouping that can be seen when looking at the data with an XSLT compatible viewer, such as a modern web browser. It's probably a good idea to make yourself familiar with the provided values, so you can understand what the collected statistics actually mean.

Synopsis:

```
 <Plugin "bind">
   URL "http://localhost:8053/"
   ParseTime       false
   OpCodes         true
   QTypes          true
   ServerStats     true
   ZoneMaintStats  true
   ResolverStats   false
   MemoryStats     true
   <View "_default">
     QTypes        true
     ResolverStats true
     CacheRRSets   true
     Zone "127.in-addr.arpa/IN"
   </View>
 </Plugin>
```

The bind plugin accepts the following configuration options:

URL URL

URL from which to retrieve the XML data. If not specified, "http://localhost:8053/" will be used.

ParseTime true|false

When set to true, the time provided by BIND will be parsed and used to dispatch the values. When set to false, the local time source is queried. This setting is set to true by default for backwards compatibility; setting this to false is recommended to avoid problems with timezones and localization.

OpCodes true|false

When enabled, statistics about the "OpCodes", for example the number of "QUERY" packets, are collected. Default: Enabled.

QTypes true|false

When enabled, the number of incoming queries by query types (for example "A", "MX", "AAAA") is collected. Default: Enabled.

ServerStats true|false

Collect global server statistics, such as requests received over IPv4 and IPv6, successful queries, and failed updates. Default: Enabled.

ZoneMaintStats true|false

Collect zone maintenance statistics, mostly information about notifications (zone updates) and zone transfers. Default: Enabled.

ResolverStats true|false

Collect resolver statistics, i. e. statistics about outgoing requests (e. g. queries over IPv4, lame servers). Since the global resolver counters apparently were removed in BIND 9.5.1 and 9.6.0, this is disabled by default. Use the ResolverStats option within a View "_default" block instead for the same functionality. Default: Disabled.

MemoryStats

Collect global memory statistics. Default: Enabled.

Timeout Milliseconds

The Timeout option sets the overall timeout for HTTP requests to URL, in milliseconds. By default, the configured Interval is used to set the timeout.

View Name

Collect statistics about a specific "view". BIND can behave different, mostly depending on the source IP-address of the request. These different configurations are called "views". If you don't use this feature, you most likely are only interested in the "_default" view. Within a <View name> block, you can specify which information you want to collect about a view. If no View block is configured, no detailed view statistics will be collected.

QTypes true|false

If enabled, the number of outgoing queries by query type (e. g. "A", "MX") is collected. Default: Enabled.

ResolverStats true|false

Collect resolver statistics, i. e. statistics about outgoing requests (e. g. queries over IPv4, lame servers). Default: Enabled.

CacheRRSets true|false

If enabled, the number of entries ("RR sets") in the view's cache by query type is collected. Negative entries (queries which resulted in an error, for example names that do not exist) are reported with a leading exclamation mark, e. g. "!A". Default: Enabled.

Zone Name

When given, collect detailed information about the given zone in the view. The information collected if very similar to the global ServerStats information (see above). You can repeat this option to collect detailed information about multiple zones.

By default no detailed zone information is collected.

### Plugin "buddyinfo"
The buddyinfo plugin collects information by reading "/proc/buddyinfo". This file contains information about the number of available contagious physical pages at the moment.

Zone ZoneName

Zone to collect info about. Will collect all zones by default.

### Plugin "capabilities"
The "capabilities" plugin collects selected static platform data using dmidecode and expose it through micro embedded webserver. The data returned by plugin is in json format.

Synopsis:

```
  <Plugin capabilities>
    Host "localhost"
    Port "9104"
  </Plugin>
```

Available configuration options for the "capabilities" plugin:

Host Hostname

Bind to the hostname / address Host. By default, the plugin will bind to the "any" address, i.e. accept packets sent to any of the hosts addresses. This option is supported only for libmicrohttpd newer than 0.9.0.

Port Port

Port the embedded webserver should listen on. Defaults to 9104.

### Plugin "ceph"
The ceph plugin collects values from JSON data to be parsed by libyajl (<https://lloyd.github.io/yajl/>) retrieved from ceph daemon admin sockets.

A separate Daemon block must be configured for each ceph daemon to be monitored. The following example will read daemon statistics from four separate ceph daemons running on the same device (two OSDs, one MON, one MDS) :

```
  <Plugin ceph>
    LongRunAvgLatency false
    ConvertSpecialMetricTypes true
    <Daemon "osd.0">
      SocketPath "/var/run/ceph/ceph-osd.0.asok"
    </Daemon>
    <Daemon "osd.1">
      SocketPath "/var/run/ceph/ceph-osd.1.asok"
    </Daemon>
    <Daemon "mon.a">
      SocketPath "/var/run/ceph/ceph-mon.ceph1.asok"
    </Daemon>
    <Daemon "mds.a">
      SocketPath "/var/run/ceph/ceph-mds.ceph1.asok"
    </Daemon>
  </Plugin>
```

The ceph plugin accepts the following configuration options:

LongRunAvgLatency true|false

If enabled, latency values(sum,count pairs) are calculated as the long run average - average since the ceph daemon was started = (sum / count). When disabled, latency values are calculated as the average since the last collection = (sum_now - sum_last) / (count_now - count_last). Default: Disabled

ConvertSpecialMetricTypes true|false

If enabled, special metrics (metrics that differ in type from similar counters) are converted to the type of those similar counters. This currently only applies to filestore.journal_wr_bytes which is a counter for OSD daemons. The ceph schema reports this metric type as a sum,count pair while similar counters are treated as derive types. When converted, the sum is used as the counter value and is treated as a derive type. When disabled, all metrics are treated as the types received from the ceph schema. Default: Enabled

Each Daemon block must have a string argument for the plugin instance name. A SocketPath is also required for each Daemon block:

Daemon DaemonName

Name to be used as the instance name for this daemon.

SocketPath SocketPath

Specifies the path to the UNIX admin socket of the ceph daemon.

### Plugin "cgroups"
This plugin collects the CPU user/system time for each cgroup by reading the cpuacct.stat files in the first cpuacct-mountpoint (typically /sys/fs/cgroup/cpu.cpuacct on machines using systemd).

CGroup Directory

Select cgroup based on the name. Whether only matching cgroups are collected or if they are ignored is controlled by the IgnoreSelected option; see below. See /"IGNORELISTS" for details.

IgnoreSelected true|false

Invert the selection: If set to true, all cgroups except the ones that match any one of the criteria are collected. By default only selected cgroups are collected if a selection is made. If no selection is configured at all, all cgroups are selected.

### Plugin "check_uptime"
The check_uptime plugin designed to check and notify about host or service status based on uptime metric.

When new metric of uptime type appears in cache, OK notification is sent. When new value for metric is less than previous value, WARNING notification is sent about host/service restart. When no new updates comes for metric and cache entry expires, then FAILURE notification is sent about unreachable host or service.

By default (when no explicit configuration), plugin checks for uptime metric.

Synopsis:

```
 <Plugin "check_uptime">
   Type "uptime"
   Type "my_uptime_type"
 </Plugin>
```

Type Type

Metric type to check for status/values. The type should consist single GAUGE data source.

### Plugin "chrony"
The "chrony" plugin collects ntp data from a chronyd server, such as clock skew and per-peer stratum.

For talking to chronyd, it mimics what the chronyc control program does on the wire.

Available configuration options for the "chrony" plugin:

Host Hostname

Hostname of the host running chronyd. Defaults to localhost.

Port Port

UDP-Port to connect to. Defaults to 323.

Timeout Timeout

Connection timeout in seconds. Defaults to 2.

### Plugin Connectivity
connectivity - Documentation of collectd's "connectivity plugin"

```
  LoadPlugin connectivity
  # ...
  <Plugin connectivity>
    Interface eth0
  </Plugin>
```

The "connectivity plugin" queries interface status using netlink (man 7 netlink) which provides information about network interfaces via the NETLINK_ROUTE family (man 7 rtnetlink). The plugin translates the value it receives to collectd's internal format and, depending on the write plugins you have loaded, it may be written to disk or submitted to another instance. The plugin listens to interfaces enumerated within the plugin configuration (see below). If no interfaces are listed, then the default is for all interfaces to be monitored.

This example shows "connectivity plugin" monitoring all interfaces. LoadPlugin connectivity <Plugin connectivity> </Plugin>

This example shows "connectivity plugin" monitoring 2 interfaces, "eth0" and "eth1". LoadPlugin connectivity <Plugin connectivity>

Interface eth0

Interface eth1 </Plugin>

This example shows "connectivity plugin" monitoring all interfaces except "eth1". LoadPlugin connectivity <Plugin connectivity>

Interface eth1

IgnoreSelected true </Plugin>

Interface interface_name

interface(s) to monitor connect to.

### Plugin "conntrack"
This plugin collects IP conntrack statistics.

OldFiles

Assume the conntrack_count and conntrack_max files to be found in /proc/sys/net/ipv4/netfilter instead of /proc/sys/net/netfilter/.

### Plugin "cpu"
The CPU plugin collects CPU usage metrics. By default, CPU usage is reported as Jiffies, using the "cpu" type. Two aggregations are available:

- Sum, per-state, over all CPUs installed in the system; and

- Sum, per-CPU, over all non-idle states of a CPU, creating an "active" state.

The two aggregations can be combined, leading to collectd only emitting a single "active" metric for the entire system. As soon as one of these aggregations (or both) is enabled, the cpu plugin will report a percentage, rather than Jiffies. In addition, you can request individual, per-state, per-CPU metrics to be reported as percentage.

The following configuration options are available:

ReportByState true|false

When set to true, the default, reports per-state metrics, e.g. "system", "user" and "idle". When set to false, aggregates (sums) all non-idle states into one "active" metric.

ReportByCpu true|false

When set to true, the default, reports per-CPU (per-core) metrics. When set to false, instead of reporting metrics for individual CPUs, only a global sum of CPU states is emitted.

ValuesPercentage false|true

This option is only considered when both, ReportByCpu and ReportByState are set to true. In this case, by default, metrics will be reported as Jiffies. By setting this option to true, you can request percentage values in the un-aggregated (per-CPU, per-state) mode as well.

ReportNumCpu false|true

When set to true, reports the number of available CPUs. Defaults to false.

ReportGuestState false|true

When set to true, reports the "guest" and "guest_nice" CPU states. Defaults to false.

SubtractGuestState false|true

This option is only considered when ReportGuestState is set to true. "guest" and "guest_nice" are included in respectively "user" and "nice". If set to true, "guest" will be subtracted from "user" and "guest_nice" will be subtracted from "nice". Defaults to true.

### Plugin "cpufreq"
This plugin is available on Linux and FreeBSD only. It doesn't have any options. On Linux it reads /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq (for the first CPU installed) to get the current CPU frequency. If this file does not exist make sure cpufreqd (<http://cpufreqd.sourceforge.net/>) or a similar tool is installed and an "cpu governor" (that's a kernel module) is loaded.

On Linux, if the system has the cpufreq-stats kernel module loaded, this plugin reports the rate of p-state (cpu frequency) transitions and the percentage of time spent in each p-state.

On FreeBSD it does a sysctl dev.cpu.0.freq and submits this as instance 0. At this time FreeBSD only has one frequency setting for all cores. See the BUGS section in the FreeBSD man page for cpufreq(4) for more details.

On FreeBSD the plugin checks the success of sysctl dev.cpu.0.freq and unregisters the plugin when this fails. A message will be logged to indicate this.

### Plugin "cpusleep"
This plugin doesn't have any options. It reads CLOCK_BOOTTIME and CLOCK_MONOTONIC and reports the difference between these clocks. Since BOOTTIME clock increments while device is suspended and MONOTONIC clock does not, the derivative of the difference between these clocks gives the relative amount of time the device has spent in suspend state. The recorded value is in milliseconds of sleep per seconds of wall clock.

### Plugin "csv"
DataDir Directory

Set the directory to store CSV-files under. Per default CSV-files are generated beneath the daemon's working directory, i. e. the BaseDir. The special strings stdout and stderr can be used to write to the standard output and standard error channels, respectively. This, of course, only makes much sense when collectd is running in foreground- or non-daemon-mode.

StoreRates true|false

If set to true, convert counter values to rates. If set to false (the default) counter values are stored as is, i. e. as an increasing integer number.

### cURL Statistics
All cURL-based plugins support collection of generic, request-based statistics. These are disabled by default and can be enabled selectively for each page or URL queried from the curl, curl_json, or curl_xml plugins. See the documentation of those plugins for specific information. This section describes the available metrics that can be configured for each plugin. All options are disabled by default.

See <http://curl.haxx.se/libcurl/c/curl_easy_getinfo.html> for more details.

TotalTime true|false

Total time of the transfer, including name resolving, TCP connect, etc.

NamelookupTime true|false

Time it took from the start until name resolving was completed.

ConnectTime true|false

Time it took from the start until the connect to the remote host (or proxy) was completed.

AppconnectTime true|false

Time it took from the start until the SSL/SSH connect/handshake to the remote host was completed.

PretransferTime true|false

Time it took from the start until just before the transfer begins.

StarttransferTime true|false

Time it took from the start until the first byte was received.

RedirectTime true|false

Time it took for all redirection steps include name lookup, connect, pre-transfer and transfer before final transaction was started.

RedirectCount true|false

The total number of redirections that were actually followed.

SizeUpload true|false

The total amount of bytes that were uploaded.

SizeDownload true|false

The total amount of bytes that were downloaded.

SpeedDownload true|false

The average download speed that curl measured for the complete download.

SpeedUpload true|false

The average upload speed that curl measured for the complete upload.

HeaderSize true|false

The total size of all the headers received.

RequestSize true|false

The total size of the issued requests.

ContentLengthDownload true|false

The content-length of the download.

ContentLengthUpload true|false

The specified size of the upload.

NumConnects true|false

The number of new connections that were created to achieve the transfer.

### Plugin "curl"
The curl plugin uses the libcurl (<http://curl.haxx.se/>) to read web pages and the match infrastructure (the same code used by the tail plugin) to use regular expressions with the received data.

The following example will read the current value of AMD stock from Google's finance page and dispatch the value to collectd.

```
  <Plugin curl>
    <Page "stock_quotes">
      Plugin "quotes"
      URL "http://finance.google.com/finance?q=NYSE%3AAMD"
      AddressFamily "any"
      User "foo"
      Password "bar"
      Digest false
      VerifyPeer true
      VerifyHost true
      CACert "/path/to/ca.crt"
      Header "X-Custom-Header: foobar"
      Post "foo=bar"
      MeasureResponseTime false
      MeasureResponseCode false
      <Match>
        Regex "<span +class=\"pr\"[^>]*> *([0-9]*\\.[0-9]+) *</span>"
        DSType "GaugeAverage"
        # Note: `stock_value' is not a standard type.
        Type "stock_value"
        Instance "AMD"
      </Match>
    </Page>
  </Plugin>
```

In the Plugin block, there may be one or more Page blocks, each defining a web page and one or more "matches" to be performed on the returned data. The string argument to the Page block is used as plugin instance.

The following options are valid within Page blocks:

Plugin Plugin

Use Plugin as the plugin name when submitting values. Defaults to "curl".

URL URL

URL of the web site to retrieve. Since a regular expression will be used to extract information from this data, non-binary data is a big plus here ;)

AddressFamily Type

IP version to resolve URL to. Useful in cases when hostname in URL resolves to both IPv4 and IPv6 addresses, and you are interested in using one of them specifically. Use "ipv4" to enforce IPv4, "ipv6" to enforce IPv6, or "any" to keep the default behavior of resolving addresses to all IP versions your system allows. If "libcurl" is compiled without IPv6 support, using "ipv6" will result in a warning and fallback to "any". If "Type" cannot be parsed, a warning will be printed and the whole Page block will be ignored.

User Name

Username to use if authorization is required to read the page.

Password Password

Password to use if authorization is required to read the page.

Digest true|false

Enable HTTP digest authentication.

VerifyPeer true|false

Enable or disable peer SSL certificate verification. See <http://curl.haxx.se/docs/sslcerts.html> for details. Enabled by default.

VerifyHost true|false

Enable or disable peer host name verification. If enabled, the plugin checks if the "Common Name" or a "Subject Alternate Name" field of the SSL certificate matches the host name provided by the URL option. If this identity check fails, the connection is aborted. Obviously, only works when connecting to a SSL enabled server. Enabled by default.

CACert file

File that holds one or more SSL certificates. If you want to use HTTPS you will possibly need this option. What CA certificates come bundled with "libcurl" and are checked by default depends on the distribution you use.

Header Header

A HTTP header to add to the request. Multiple headers are added if this option is specified more than once.

Post Body

Specifies that the HTTP operation should be a POST instead of a GET. The complete data to be posted is given as the argument. This option will usually need to be accompanied by a Header option to set an appropriate "Content-Type" for the post body (e.g. to "application/x-www-form-urlencoded").

MeasureResponseTime true|false

Measure response time for the request. If this setting is enabled, Match blocks (see below) are optional. Disabled by default. Beware that requests will get aborted if they take too long to complete. Adjust Timeout accordingly if you expect MeasureResponseTime to report such slow requests.

This option is similar to enabling the TotalTime statistic but it's measured by collectd instead of cURL.

MeasureResponseCode true|false

Measure response code for the request. If this setting is enabled, Match blocks (see below) are optional. Disabled by default.

<Statistics>

One Statistics block can be used to specify cURL statistics to be collected for each request to the remote web site. See the section "cURL Statistics" above for details. If this setting is enabled, Match blocks (see below) are optional.

<Match>

One or more Match blocks that define how to match information in the data returned by "libcurl". The "curl" plugin uses the same infrastructure that's used by the "tail" plugin, so please see the documentation of the "tail" plugin below on how matches are defined. If the MeasureResponseTime or MeasureResponseCode options are set to true, Match blocks are optional.

Interval Interval

Sets the interval (in seconds) in which the values will be collected from this URL. By default the global Interval setting will be used.

Timeout Milliseconds

The Timeout option sets the overall timeout for HTTP requests to URL, in milliseconds. By default, the configured Interval is used to set the timeout. Prior to version 5.5.0, there was no timeout and requests could hang indefinitely. This legacy behaviour can be achieved by setting the value of Timeout to 0. If Timeout is 0 or bigger than the Interval, keep in mind that each slow network connection will stall one read thread. Adjust the ReadThreads global setting accordingly to prevent this from blocking other plugins.

### Plugin "curl_json"
The curl_json plugin collects values from JSON data to be parsed by libyajl (<https://lloyd.github.io/yajl/>) retrieved via either libcurl (<http://curl.haxx.se/>) or read directly from a unix socket. The former can be used, for example, to collect values from CouchDB documents (which are stored JSON notation), and the latter to collect values from a uWSGI stats socket.

The following example will collect several values from the built-in "_stats" runtime statistics module of CouchDB (<http://wiki.apache.org/couchdb/Runtime_Statistics>).

```
  <Plugin curl_json>
    <URL "http://localhost:5984/_stats">
      AddressFamily "any"
      Instance "httpd"
      <Key "httpd/requests/count">
        Type "http_requests"
      </Key>
      <Key "httpd_request_methods/*/count">
        Type "http_request_methods"
      </Key>
      <Key "httpd_status_codes/*/count">
        Type "http_response_codes"
      </Key>
    </URL>
  </Plugin>
```

This example will collect data directly from a uWSGI "Stats Server" socket.

```
  <Plugin curl_json>
    <Sock "/var/run/uwsgi.stats.sock">
      Instance "uwsgi"
      <Key "workers/*/requests">
        Type "http_requests"
      </Key>
      <Key "workers/*/apps/*/requests">
        Type "http_requests"
      </Key>
    </Sock>
  </Plugin>
```

In the Plugin block, there may be one or more URL blocks, each defining a URL to be fetched via HTTP (using libcurl) or Sock blocks defining a unix socket to read JSON from directly. Each of these blocks may have one or more Key blocks.

The Key string argument must be in a path format. Each component is used to match the key from a JSON map or the index of an JSON array. If a path component of a Key is a * wildcard, the values for all map keys or array indices will be collectd.

The following options are valid within URL blocks:

AddressFamily Type

IP version to resolve URL to. Useful in cases when hostname in URL resolves to both IPv4 and IPv6 addresses, and you are interested in using one of them specifically. Use "ipv4" to enforce IPv4, "ipv6" to enforce IPv6, or "any" to keep the default behavior of resolving addresses to all IP versions your system allows. If "libcurl" is compiled without IPv6 support, using "ipv6" will result in a warning and fallback to "any". If "Type" cannot be parsed, a warning will be printed and the whole URL block will be ignored.

Host Name

Use Name as the host name when submitting values. Defaults to the global host name setting.

Plugin Plugin

Use Plugin as the plugin name when submitting values. Defaults to "curl_json".

Instance Instance

Sets the plugin instance to Instance.

Interval Interval

Sets the interval (in seconds) in which the values will be collected from this URL. By default the global Interval setting will be used.

User Name

Password Password

Digest true|false

VerifyPeer true|false

VerifyHost true|false

CACert file

Header Header

Post Body

Timeout Milliseconds

These options behave exactly equivalent to the appropriate options of the cURL plugin. Please see there for a detailed description.

<Statistics>

One Statistics block can be used to specify cURL statistics to be collected for each request to the remote URL. See the section "cURL Statistics" above for details.

The following options are valid within Key blocks:

Type Type

Sets the type used to dispatch the values to the daemon. Detailed information about types and their configuration can be found in types.db(5). This option is mandatory.

Instance Instance

Type-instance to use. Defaults to the current map key or current string array element value.

### Plugin "curl_jolokia"
The curl_jolokia plugin collects values from MBeanServevr - servlet engines equipped with the jolokia (<https://jolokia.org>) MBean. It sends a pre-configured JSON-Postbody to the servlet via HTTP commanding the jolokia Bean to reply with a singe JSON equipped with all JMX counters requested. By reducing TCP roundtrips in comparison to conventional JMX clients that query one value via tcp at a time, it can return hundrets of values in one roundtrip. Moreof - no java binding is required in collectd to do so.

It uses libyajl (<https://lloyd.github.io/yajl/>) to parse the Jolokia JSON reply retrieved via libcurl (<http://curl.haxx.se/>)

```
 <Plugin curl_jolokia>
   <URL "http://10.10.10.10:7101/jolokia-war-1.2.0/?ignoreErrors=true&canonicalNaming=false";>
     Host "_APPPERF_JMX"
     User "webloginname"
     Password "passvoid"
     Post <JOLOKIA json post data>
   <BeanName "PS_Scavenge">
        MBean "java.lang:name=PS Scavenge,type=GarbageCollector"
        BeanNameSpace "java_lang"
        <AttributeName "collectiontime" >
               Attribute "CollectionTime"
               type "gauge"
        </AttributeName>
        <AttributeName "collectioncount" >
               Attribute "CollectionCount"
               type "gauge"
        </AttributeName>
   </BeanName>
  </Plugin>
```

The plugin is intended to be written in a simple manner. Thus it doesn't try to solve the task of generating the jolokia post data, or automatically map the values, but rather leans on a verbose config containing the prepared flat JSON post data and a config section per gauge transformed (as one sample shown above). However, Jolokia can output all available gauges, and we have a python script to filter them, and generate a configuration for you:

```
  jolokia_2_collectcfg.py
```

it can gather all interesting gauges, write a simple one value per line config for itself and subsequent calls. You can remove lines from this file manually, or create filter lists. You then use the script to generate a collectd config. The script can then inspect data files from some testruns, and remove all gauges, that don't contain any movement.

The base config looks like this:

The following options are valid within URL blocks:

Host Name

Use Name as the host name when submitting values. Defaults to the global host name setting.

Plugin Plugin

Use Plugin as the plugin name when submitting values. Defaults to "curl_jolokia".

Instance Instance

Sets the plugin instance to Instance.

Interval Interval

Sets the interval (in seconds) in which the values will be collected from this URL. By default the global Interval setting will be used.

User Name

Password Password

Digest true|false

VerifyPeer true|false

VerifyHost true|false

CACert file

Header Header

Post Body

Timeout Milliseconds

These options behave exactly equivalent to the appropriate options of the cURL plugin. Please see there for a detailed description.

<BeanName>

One BeanName block configures the translation of the gauges of one bean to their respective collectd names, where BeanName sets the main name.

MBean MBean

The name of the Bean on the server

BeanNameSpace BeanNameSpace

The name space the Bean resides under

AttributeName AttributeName

A bean can contain several Attributes with gauges. Each one can be matched by a AttributeName section or be ignored.

Attribute Attribute

How should this attribute be called under the BeanName in the collectd hierarchy?

Type Type

Sets the type used to dispatch the values to the daemon. Detailed information about types and their configuration can be found in types.db(5). This option is mandatory.

### Plugin "curl_xml"
The curl_xml plugin uses libcurl (<http://curl.haxx.se/>) and libxml2 (<http://xmlsoft.org/>) to retrieve XML data via cURL.

```
 <Plugin "curl_xml">
   <URL "http://localhost/stats.xml">
     AddressFamily "any"
     Host "my_host"
     #Plugin "curl_xml"
     Instance "some_instance"
     User "collectd"
     Password "thaiNg0I"
     VerifyPeer true
     VerifyHost true
     CACert "/path/to/ca.crt"
     Header "X-Custom-Header: foobar"
     Post "foo=bar"
     <XPath "table[@id=\"magic_level\"]/tr">
       Type "magic_level"
       #InstancePrefix "prefix-"
       InstanceFrom "td[1]"
       #PluginInstanceFrom "td[1]"
       ValuesFrom "td[2]/span[@class=\"level\"]"
     </XPath>
   </URL>
 </Plugin>
```

In the Plugin block, there may be one or more URL blocks, each defining a URL to be fetched using libcurl. Within each URL block there are options which specify the connection parameters, for example authentication information, and one or more XPath blocks.

Each XPath block specifies how to get one type of information. The string argument must be a valid XPath expression which returns a list of "base elements". One value is dispatched for each "base element". The type instance and values are looked up using further XPath expressions that should be relative to the base element.

Within the URL block the following options are accepted:

AddressFamily Type

IP version to resolve URL to. Useful in cases when hostname in URL resolves to both IPv4 and IPv6 addresses, and you are interested in using one of them specifically. Use "ipv4" to enforce IPv4, "ipv6" to enforce IPv6, or "any" to keep the default behavior of resolving addresses to all IP versions your system allows. If "libcurl" is compiled without IPv6 support, using "ipv6" will result in a warning and fallback to "any". If "Type" cannot be parsed, a warning will be printed and the whole URL block will be ignored.

Host Name

Use Name as the host name when submitting values. Defaults to the global host name setting.

Plugin Plugin

Use Plugin as the plugin name when submitting values. Defaults to 'curl_xml'.

Instance Instance

Use Instance as the plugin instance when submitting values. May be overridden by PluginInstanceFrom option inside XPath blocks. Defaults to an empty string (no plugin instance).

Interval Interval

Sets the interval (in seconds) in which the values will be collected from this URL. By default the global Interval setting will be used.

Namespace Prefix URL

If an XPath expression references namespaces, they must be specified with this option. Prefix is the "namespace prefix" used in the XML document. URL is the "namespace name", an URI reference uniquely identifying the namespace. The option can be repeated to register multiple namespaces. Examples:

```
  Namespace "s" "http://schemas.xmlsoap.org/soap/envelope/"
  Namespace "m" "http://www.w3.org/1998/Math/MathML"

```

User User

Password Password

Digest true|false

VerifyPeer true|false

VerifyHost true|false

CACert CA Cert File

Header Header

Post Body

Timeout Milliseconds

These options behave exactly equivalent to the appropriate options of the cURL plugin. Please see there for a detailed description.

<Statistics>

One Statistics block can be used to specify cURL statistics to be collected for each request to the remote URL. See the section "cURL Statistics" above for details.

<XPath XPath-expression>

Within each URL block, there must be one or more XPath blocks. Each XPath block specifies how to get one type of information. The string argument must be a valid XPath expression which returns a list of "base elements". One value is dispatched for each "base element". Within the XPath block the following options are accepted:

Type Type

Specifies the Type used for submitting patches. This determines the number of values that are required / expected and whether the strings are parsed as signed or unsigned integer or as double values. See types.db(5) for details. This option is required.

InstancePrefix InstancePrefix

Prefix the type instance with InstancePrefix. The values are simply concatenated together without any separator. This option is optional.

InstanceFrom InstanceFrom

Specifies a XPath expression to use for determining the type instance. The XPath expression must return exactly one element. The element's value is then used as type instance, possibly prefixed with InstancePrefix (see above).

PluginInstanceFrom PluginInstanceFrom

Specifies a XPath expression to use for determining the plugin instance. The XPath expression must return exactly one element. The element's value is then used as plugin instance.

If the "base XPath expression" (the argument to the XPath block) returns exactly one argument, then InstanceFrom and PluginInstanceFrom may be omitted. Otherwise, at least one of InstanceFrom or PluginInstanceFrom is required.

ValuesFrom ValuesFrom [ValuesFrom ...]

Specifies one or more XPath expression to use for reading the values. The number of XPath expressions must match the number of data sources in the type specified with Type (see above). Each XPath expression must return exactly one element. The element's value is then parsed as a number and used as value for the appropriate value in the value list dispatched to the daemon. This option is required.

### Plugin "dbi"
This plugin uses the dbi library (<http://libdbi.sourceforge.net/>) to connect to various databases, execute SQL statements and read back the results. dbi is an acronym for "database interface" in case you were wondering about the name. You can configure how each column is to be interpreted and the plugin will generate one or more data sets from each row returned according to these rules.

Because the plugin is very generic, the configuration is a little more complex than those of other plugins. It usually looks something like this:

```
  <Plugin dbi>
    <Query "out_of_stock">
      Statement "SELECT category, COUNT(*) AS value FROM products WHERE in_stock = 0 GROUP BY category"
      # Use with MySQL 5.0.0 or later
      MinVersion 50000
      <Result>
        Type "gauge"
        InstancePrefix "out_of_stock"
        InstancesFrom "category"
        ValuesFrom "value"
      </Result>
    </Query>
    <Database "product_information">
      #Plugin "warehouse"
      Driver "mysql"
      Interval 120
      DriverOption "host" "localhost"
      DriverOption "username" "collectd"
      DriverOption "password" "aZo6daiw"
      DriverOption "dbname" "prod_info"
      SelectDB "prod_info"
      Query "out_of_stock"
    </Database>
  </Plugin>
```

The configuration above defines one query with one result and one database. The query is then linked to the database with the Query option within the <Database> block. You can have any number of queries and databases and you can also use the Include statement to split up the configuration file in multiple, smaller files. However, the <Query> block must precede the <Database> blocks, because the file is interpreted from top to bottom!

The following is a complete list of options:

Query blocks

Query blocks define SQL statements and how the returned data should be interpreted. They are identified by the name that is given in the opening line of the block. Thus the name needs to be unique. Other than that, the name is not used in collectd.

In each Query block, there is one or more Result blocks. Result blocks define which column holds which value or instance information. You can use multiple Result blocks to create multiple values from one returned row. This is especially useful, when queries take a long time and sending almost the same query again and again is not desirable.

Example:

```
  <Query "environment">
    Statement "select station, temperature, humidity from environment"
    <Result>
      Type "temperature"
      # InstancePrefix "foo"
      InstancesFrom "station"
      ValuesFrom "temperature"
    </Result>
    <Result>
      Type "humidity"
      InstancesFrom "station"
      ValuesFrom "humidity"
    </Result>
  </Query>
```

The following options are accepted:

Statement SQL

Sets the statement that should be executed on the server. This is not interpreted by collectd, but simply passed to the database server. Therefore, the SQL dialect that's used depends on the server collectd is connected to. The query has to return at least two columns, one for the instance and one value. You cannot omit the instance, even if the statement is guaranteed to always return exactly one line. In that case, you can usually specify something like this:

```
  Statement "SELECT \"instance\", COUNT(*) AS value FROM table"

```

(That works with MySQL but may not be valid SQL according to the spec. If you use a more strict database server, you may have to select from a dummy table or something.)

Please note that some databases, for example Oracle, will fail if you include a semicolon at the end of the statement.

MinVersion Version

MaxVersion Value

Only use this query for the specified database version. You can use these options to provide multiple queries with the same name but with a slightly different syntax. The plugin will use only those queries, where the specified minimum and maximum versions fit the version of the database in use. The database version is determined by "dbi_conn_get_engine_version", see the libdbi documentation <http://libdbi.sourceforge.net/docs/programmers-guide/reference-conn.html#DBI-CONN-GET-ENGINE-VERSION> for details. Basically, each part of the version is assumed to be in the range from 00 to 99 and all dots are removed. So version "4.1.2" becomes "40102", version "5.0.42" becomes "50042".

Warning: The plugin will use all matching queries, so if you specify multiple queries with the same name and overlapping ranges, weird stuff will happen. Don't to it! A valid example would be something along these lines:

```
  MinVersion 40000
  MaxVersion 49999
  ...
  MinVersion 50000
  MaxVersion 50099
  ...
  MinVersion 50100
  # No maximum

```

In the above example, there are three ranges that don't overlap. The last one goes from version "5.1.0" to infinity, meaning "all later versions". Versions before "4.0.0" are not specified.

Type Type

The type that's used for each line returned. See types.db(5) for more details on how types are defined. In short: A type is a predefined layout of data and the number of values and type of values has to match the type definition. If you specify "temperature" here, you need exactly one gauge column. If you specify "if_octets", you will need two counter columns. See the ValuesFrom setting below.

There must be exactly one Type option inside each Result block.

InstancePrefix prefix

Prepends prefix to the type instance. If InstancesFrom (see below) is not given, the string is simply copied. If InstancesFrom is given, prefix and all strings returned in the appropriate columns are concatenated together, separated by dashes ("-").

InstancesFrom column0 [column1 ...]

Specifies the columns whose values will be used to create the "type-instance" for each row. If you specify more than one column, the value of all columns will be joined together with dashes ("-") as separation characters. The plugin itself does not check whether or not all built instances are different. It's your responsibility to assure that each is unique. This is especially true, if you do not specify InstancesFrom: You have to make sure that only one row is returned in this case.

If neither InstancePrefix nor InstancesFrom is given, the type-instance will be empty.

ValuesFrom column0 [column1 ...]

Names the columns whose content is used as the actual data for the data sets that are dispatched to the daemon. How many such columns you need is determined by the Type setting above. If you specify too many or not enough columns, the plugin will complain about that and no data will be submitted to the daemon. The actual data type in the columns is not that important. The plugin will automatically cast the values to the right type if it know how to do that. So it should be able to handle integer an floating point types, as well as strings (if they include a number at the beginning).

There must be at least one ValuesFrom option inside each Result block.

MetadataFrom [column0 column1 ...]

Names the columns whose content is used as metadata for the data sets that are dispatched to the daemon. The actual data type in the columns is not that important. The plugin will automatically cast the values to the right type if it know how to do that. So it should be able to handle integer an floating point types, as well as strings (if they include a number at the beginning).

Database blocks

Database blocks define a connection to a database and which queries should be sent to that database. Since the used "dbi" library can handle a wide variety of databases, the configuration is very generic. If in doubt, refer to libdbi's documentation - we stick as close to the terminology used there.

Each database needs a "name" as string argument in the starting tag of the block. This name will be used as "PluginInstance" in the values submitted to the daemon. Other than that, that name is not used.

Plugin Plugin

Use Plugin as the plugin name when submitting query results from this Database. Defaults to "dbi".

Interval Interval

Sets the interval (in seconds) in which the values will be collected from this database. By default the global Interval setting will be used.

Driver Driver

Specifies the driver to use to connect to the database. In many cases those drivers are named after the database they can connect to, but this is not a technical necessity. These drivers are sometimes referred to as "DBD", DataBase Driver, and some distributions ship them in separate packages. Drivers for the "dbi" library are developed by the libdbi-drivers project at <http://libdbi-drivers.sourceforge.net/>. You need to give the driver name as expected by the "dbi" library here. You should be able to find that in the documentation for each driver. If you mistype the driver name, the plugin will dump a list of all known driver names to the log.

DriverOption Key Value

Sets driver-specific options. What option a driver supports can be found in the documentation for each driver, somewhere at <http://libdbi-drivers.sourceforge.net/>. However, the options "host", "username", "password", and "dbname" seem to be de facto standards. DBDs can register two types of options: String options and numeric options. The plugin will use the "dbi_conn_set_option" function when the configuration provides a string and the "dbi_conn_require_option_numeric" function when the configuration provides a number. So these two lines will actually result in different calls being used:

```
  DriverOption "Port" 1234      # numeric
  DriverOption "Port" "1234"    # string

```

Unfortunately, drivers are not too keen to report errors when an unknown option is passed to them, so invalid settings here may go unnoticed. This is not the plugin's fault, it will report errors if it gets them from the library / the driver. If a driver complains about an option, the plugin will dump a complete list of all options understood by that driver to the log. There is no way to programmatically find out if an option expects a string or a numeric argument, so you will have to refer to the appropriate DBD's documentation to find this out. Sorry.

SelectDB Database

In some cases, the database name you connect with is not the database name you want to use for querying data. If this option is set, the plugin will "select" (switch to) that database after the connection is established.

Query QueryName

Associates the query named QueryName with this database connection. The query needs to be defined before this statement, i. e. all query blocks you want to refer to must be placed above the database block you want to refer to them from.

Host Hostname

Sets the host field of value lists to Hostname when dispatching values. Defaults to the global hostname setting.

### Plugin "dcpmm"
The dcpmm plugin will collect Intel(R) Optane(TM) DC Persistent Memory related performance statistics. The plugin requires root privileges to perform the statistics collection.

Synopsis:

```
 <Plugin "dcpmm">
   Interval 10.0
   CollectHealth false
   CollectPerfMetrics true
   EnableDispatchAll false
 </Plugin>
```

Interval time in seconds

Sets the Interval (in seconds) in which the values will be collected. Defaults to "global Interval" value. This will override the global Interval for dcpmm plugin. None of the other plugins will be affected.

CollectHealth true|false

Collects health information. CollectHealth and CollectPerfMetrics cannot be true at the same time. Defaults to "false". The health information metrics are the following:

health_status Overall health summary (0: normal | 1: non-critical | 2: critical | 3: fatal).

lifespan_remaining The moduleXs remaining life as a percentage value of factory expected life span.

lifespan_used The moduleXs used life as a percentage value of factory expected life span.

power_on_time The lifetime the DIMM has been powered on in seconds.

uptime The current uptime of the DIMM for the current power cycle in seconds.

last_shutdown_time The time the system was last shutdown. The time is represented in epoch (seconds).

media_temperature The mediaXs current temperature in degree Celsius.

controller_temperature The controllerXs current temperature in degree Celsius.

max_media_temperature The mediaXs the highest temperature reported in degree Celsius.

max_controller_temperature The controllerXs highest temperature reported in degree Celsius.

tsc_cycles The number of tsc cycles during each interval.

epoch The timestamp in seconds at which the metrics are collected from DCPMM DIMMs.

CollectPerfMetrics true|false

Collects memory performance metrics. CollectHealth and CollectPerfMetrics cannot be true at the same time. Defaults to "true". The memory performance metrics are the following:

total_bytes_read Number of bytes transacted by the read operations.

total_bytes_written Number of bytes transacted by the write operations.

read_64B_ops_rcvd Number of read operations performed to the physical media in 64 bytes granularity.

write_64B_ops_rcvd Number of write operations performed to the physical media in 64 bytes granularity.

media_read_ops Number of read operations performed to the physical media.

media_write_ops Number of write operations performed to the physical media.

host_reads Number of read operations received from the CPU (memory controller).

host_writes Number of write operations received from the CPU (memory controller).

read_hit_ratio Measures the efficiency of the buffer in the read path. Range of 0.0 - 1.0.

write_hit_ratio Measures the efficiency of the buffer in the write path. Range of 0.0 - 1.0.

tsc_cycles The number of tsc cycles during each interval.

epoch The timestamp in seconds at which the metrics are collected from DCPMM DIMMs.

EnableDispatchAll false

This parameter helps to seamlessly enable simultaneous health and memory perf metrics collection in future. This is unused at the moment and must always be false.

### Plugin "df"
Device Device

Select partitions based on the devicename. See /"IGNORELISTS" for details.

MountPoint Directory

Select partitions based on the mountpoint. See /"IGNORELISTS" for details.

FSType FSType

Select partitions based on the filesystem type. See /"IGNORELISTS" for details.

IgnoreSelected true|false

Invert the selection: If set to true, all partitions except the ones that match any one of the criteria are collected. By default only selected partitions are collected if a selection is made. If no selection is configured at all, all partitions are selected.

LogOnce false|false

Only log stat() errors once.

ReportByDevice true|false

Report using the device name rather than the mountpoint. i.e. with this false, (the default), it will report a disk as "root", but with it true, it will be "sda1" (or whichever).

ReportInodes true|false

Enables or disables reporting of free, reserved and used inodes. Defaults to inode collection being disabled. Enable this option if inodes are a scarce resource for you, usually because many small files are stored on the disk. This is a usual scenario for mail transfer agents and web caches.

ValuesAbsolute true|false

Enables or disables reporting of free and used disk space in 1K-blocks. Defaults to true.

ValuesPercentage false|true

Enables or disables reporting of free and used disk space in percentage. Defaults to false. This is useful for deploying collectd on the cloud, where machines with different disk size may exist. Then it is more practical to configure thresholds based on relative disk size.

### Plugin "disk"
The "disk" plugin collects information about the usage of physical disks and logical disks (partitions). Values collected are the number of octets written to and read from a disk or partition, the number of read/write operations issued to the disk and a rather complex "time" it took for these commands to be issued.

Using the following two options you can ignore some disks or configure the collection only of specific disks.

Disk Name

Select the disk Name. Whether it is collected or ignored depends on the IgnoreSelected setting, see below. As with other plugins that use the daemon's ignorelist functionality, a string that starts and ends with a slash is interpreted as a regular expression. Examples:

```
  Disk "sdd"
  Disk "/hda[34]/"

```

See /"IGNORELISTS" for details.

IgnoreSelected true|false

Sets whether selected disks, i. e. the ones matches by any of the Disk statements, are ignored or if all other disks are ignored. The behavior (hopefully) is intuitive: If no Disk option is configured, all disks are collected. If at least one Disk option is given and no IgnoreSelected or set to false, only matching disks will be collected. If IgnoreSelected is set to true, all disks are collected except the ones matched.

UseBSDName true|false

Whether to use the device's "BSD Name", on Mac OS X, instead of the default major/minor numbers. Requires collectd to be built with Apple's IOKitLib support.

UdevNameAttr Attribute

Attempt to override disk instance name with the value of a specified udev attribute when built with libudev. If the attribute is not defined for the given device, the default name is used. Example:

```
  UdevNameAttr "DM_NAME"

```

Please note that using an attribute that does not differentiate between the whole disk and its particular partitions (like ID_SERIAL) will result in data about the whole disk and each partition being mixed together incorrectly. In this case, you can use ID_COLLECTD attribute that is provided by contrib/99-storage-collectd.rules udev rule file instead.

### Plugin "dns"
Interface Interface

The dns plugin uses libpcap to capture dns traffic and analyzes it. This option sets the interface that should be used. If this option is not set, or set to "any", the plugin will try to get packets from all interfaces. This may not work on certain platforms, such as Mac OS X.

IgnoreSource IP-address

Ignore packets that originate from this address.

SelectNumericQueryTypes true|false

Enabled by default, collects unknown (and thus presented as numeric only) query types.

### Plugin "dpdkevents"
The dpdkevents plugin collects events from DPDK such as link status of network ports and Keep Alive status of DPDK logical cores. In order to get Keep Alive events following requirements must be met: - DPDK >= 16.07 - support for Keep Alive implemented in DPDK application. More details can be found here: http://dpdk.org/doc/guides/sample_app_ug/keep_alive.html

Synopsis:

```
 <Plugin "dpdkevents">
   <EAL>
     Coremask "0x1"
     MemoryChannels "4"
     FilePrefix "rte"
   </EAL>
   <Event "link_status">
     SendEventsOnUpdate true
     EnabledPortMask 0xffff
     PortName "interface1"
     PortName "interface2"
     SendNotification false
   </Event>
   <Event "keep_alive">
     SendEventsOnUpdate true
     LCoreMask "0xf"
     KeepAliveShmName "/dpdk_keepalive_shm_name"
     SendNotification false
   </Event>
 </Plugin>
```

Options:

The EAL block

Coremask Mask

Memorychannels Channels

Number of memory channels per processor socket.

FilePrefix File

The prefix text used for hugepage filenames. The filename will be set to /var/run/.<prefix>_config where prefix is what is passed in by the user.

The Event block

The Event block defines configuration for specific event. It accepts a single argument which specifies the name of the event.

Link Status event

SendEventOnUpdate true|false

If set to true link status value will be dispatched only when it is different from previously read value. This is an optional argument - default value is true.

EnabledPortMask Mask

A hexidecimal bit mask of the DPDK ports which should be enabled. A mask of 0x0 means that all ports will be disabled. A bitmask of all F's means that all ports will be enabled. This is an optional argument - by default all ports are enabled.

PortName Name

A string containing an optional name for the enabled DPDK ports. Each PortName option should contain only one port name; specify as many PortName options as desired. Default naming convention will be used if PortName is blank. If there are less PortName options than there are enabled ports, the default naming convention will be used for the additional ports.

SendNotification true|false

If set to true, link status notifications are sent, instead of link status being collected as a statistic. This is an optional argument - default value is false.

Keep Alive event

SendEventOnUpdate true|false

If set to true keep alive value will be dispatched only when it is different from previously read value. This is an optional argument - default value is true.

LCoreMask Mask

An hexadecimal bit mask of the logical cores to monitor keep alive state.

KeepAliveShmName Name

Shared memory name identifier that is used by secondary process to monitor the keep alive cores state.

SendNotification true|false

If set to true, keep alive notifications are sent, instead of keep alive information being collected as a statistic. This is an optional argument - default value is false.

### Plugin "dpdkstat"
The dpdkstat plugin collects information about DPDK interfaces using the extended NIC stats API in DPDK.

Synopsis:

```
 <Plugin "dpdkstat">
   <EAL>
     Coremask "0x4"
     MemoryChannels "4"
     FilePrefix "rte"
     SocketMemory "1024"
     LogLevel "7"
     RteDriverLibPath "/usr/lib/dpdk-pmd"
   </EAL>
   SharedMemObj "dpdk_collectd_stats_0"
   EnabledPortMask 0xffff
   PortName "interface1"
   PortName "interface2"
 </Plugin>
```

Options:

The EAL block

Coremask Mask

A string containing an hexadecimal bit mask of the cores to run on. Note that core numbering can change between platforms and should be determined beforehand.

Memorychannels Channels

A string containing a number of memory channels per processor socket.

FilePrefix File

The prefix text used for hugepage filenames. The filename will be set to /var/run/.<prefix>_config where prefix is what is passed in by the user.

SocketMemory MB

A string containing amount of Memory to allocate from hugepages on specific sockets in MB. This is an optional value.

LogLevel LogLevel_number

A string containing log level number. This parameter is optional. If parameter is not present then default value "7" - (INFO) is used. Value "8" - (DEBUG) can be set to enable debug traces.

RteDriverLibPath Path

A string containing path to shared pmd driver lib or path to directory, where shared pmd driver libs are available. This parameter is optional. This parameter enable loading of shared pmd driver libs from defined path. E.g.: "/usr/lib/dpdk-pmd/librte_pmd_i40e.so" or "/usr/lib/dpdk-pmd"

SharedMemObj Mask

A string containing the name of the shared memory object that should be used to share stats from the DPDK secondary process to the collectd dpdkstat plugin. Defaults to dpdk_collectd_stats if no other value is configured.

EnabledPortMask Mask

A hexidecimal bit mask of the DPDK ports which should be enabled. A mask of 0x0 means that all ports will be disabled. A bitmask of all Fs means that all ports will be enabled. This is an optional argument - default is all ports enabled.

PortName Name

A string containing an optional name for the enabled DPDK ports. Each PortName option should contain only one port name; specify as many PortName options as desired. Default naming convention will be used if PortName is blank. If there are less PortName options than there are enabled ports, the default naming convention will be used for the additional ports.

### Plugin "dpdk_telemetry"
The dpdk_telemetry plugin collects DPDK ethernet device metrics via dpdk_telemetry library.

The plugin retrieves metrics from a DPDK packet forwarding application by sending the JSON formatted message via a UNIX domain socket. The DPDK telemetry component will respond with a JSON formatted reply, delivering the requested metrics. The plugin parses the JSON data, and publishes the metric values to collectd for further use.

Synopsis:

```
  <Plugin dpdk_telemetry>
    ClientSocketPath "/var/run/.client"
    DpdkSocketPath "/var/run/dpdk/rte/telemetry"
  </Plugin>
```

Options:

ClientSocketPath Client_Path

The UNIX domain client socket at Client_Path to receive messages from DPDK telemetry library. Defaults to "/var/run/.client".

DpdkSocketPath Dpdk_Path

The UNIX domain DPDK telemetry socket to be connected at Dpdk_Path to send messages. Defaults to "/var/run/dpdk/rte/telemetry".

### Plugin "email"
SocketFile Path

Sets the socket-file which is to be created.

SocketGroup Group

If running as root change the group of the UNIX-socket after it has been created. Defaults to collectd.

SocketPerms Permissions

Change the file permissions of the UNIX-socket after it has been created. The permissions must be given as a numeric, octal value as you would pass to chmod(1). Defaults to 0770.

MaxConns Number

Sets the maximum number of connections that can be handled in parallel. Since this many threads will be started immediately setting this to a very high value will waste valuable resources. Defaults to 5 and will be forced to be at most 16384 to prevent typos and dumb mistakes.

### Plugin "ethstat"
The ethstat plugin collects information about network interface cards (NICs) by talking directly with the underlying kernel driver using ioctl(2).

Synopsis:

```
 <Plugin "ethstat">
   Interface "eth0"
   Map "rx_csum_offload_errors" "if_rx_errors" "checksum_offload"
   Map "multicast" "if_multicast"
 </Plugin>
```

Options:

Interface Name

Collect statistical information about interface Name.

Map Name Type [TypeInstance]

By default, the plugin will submit values as type "derive" and type instance set to Name, the name of the metric as reported by the driver. If an appropriate Map option exists, the given Type and, optionally, TypeInstance will be used.

MappedOnly true|false

When set to true, only metrics that can be mapped to a type will be collected, all other metrics will be ignored. Defaults to false.

### Plugin "exec"
Please make sure to read collectd-exec(5) before using this plugin. It contains valuable information on when the executable is executed and the output that is expected from it.

Exec User[:[Group]] Executable [<arg> [<arg> ...]]

NotificationExec User[:[Group]] Executable [<arg> [<arg> ...]]

Execute the executable Executable as user User. If the user name is followed by a colon and a group name, the effective group is set to that group. The real group and saved-set group will be set to the default group of that user. If no group is given the effective group ID will be the same as the real group ID. Please note that in order to change the user and/or group the daemon needs superuser privileges. If the daemon is run as an unprivileged user you must specify the same user/group here. If the daemon is run with superuser privileges, you must supply a non-root user here.

The executable may be followed by optional arguments that are passed to the program. Please note that due to the configuration parsing numbers and boolean values may be changed. If you want to be absolutely sure that something is passed as-is please enclose it in quotes.

The Exec and NotificationExec statements change the semantics of the programs executed, i. e. the data passed to them and the response expected from them. This is documented in great detail in collectd-exec(5).

### Plugin "fhcount"
The "fhcount" plugin provides statistics about used, unused and total number of file handles on Linux.

The fhcount plugin provides the following configuration options:

ValuesAbsolute true|false

Enables or disables reporting of file handles usage in absolute numbers, e.g. file handles used. Defaults to true.

ValuesPercentage false|true

Enables or disables reporting of file handles usage in percentages, e.g. percent of file handles used. Defaults to false.

### Plugin "filecount"
The "filecount" plugin counts the number of files in a certain directory (and its subdirectories) and their combined size. The configuration is very straight forward:

```
  <Plugin "filecount">
    <Directory "/var/qmail/queue/mess">
      Instance "qmail-message"
    </Directory>
    <Directory "/var/qmail/queue/todo">
      Instance "qmail-todo"
    </Directory>
    <Directory "/var/lib/php5">
      Instance "php5-sessions"
      Name "sess_*"
    </Directory>
  </Plugin>
```

The example above counts the number of files in QMail's queue directories and the number of PHP5 sessions. Jfiy: The "todo" queue holds the messages that QMail has not yet looked at, the "message" queue holds the messages that were classified into "local" and "remote".

As you can see, the configuration consists of one or more "Directory" blocks, each of which specifies a directory in which to count the files. Within those blocks, the following options are recognized:

Plugin Plugin

Use Plugin as the plugin name when submitting values. Defaults to filecount.

Instance Instance

Sets the plugin instance to Instance. If not given, the instance is set to the directory name with all slashes replaced by underscores and all leading underscores removed. Empty value is allowed.

Name Pattern

Only count files that match Pattern, where Pattern is a shell-like wildcard as understood by fnmatch(3). Only the filename is checked against the pattern, not the entire path. In case this makes it easier for you: This option has been named after the -name parameter to find(1).

MTime Age

Count only files of a specific age: If Age is greater than zero, only files that haven't been touched in the last Age seconds are counted. If Age is a negative number, this is inversed. For example, if -60 is specified, only files that have been modified in the last minute will be counted. The number can also be followed by a "multiplier" to easily specify a larger timespan. When given in this notation, the argument must in quoted, i. e. must be passed as string. So the -60 could also be written as "-1m" (one minute). Valid multipliers are "s" (second), "m" (minute), "h" (hour), "d" (day), "w" (week), and "y" (year). There is no "month" multiplier. You can also specify fractional numbers, e. g. "0.5d" is identical to "12h".

Size Size

Count only files of a specific size. When Size is a positive number, only files that are at least this big are counted. If Size is a negative number, this is inversed, i. e. only files smaller than the absolute value of Size are counted. As with the MTime option, a "multiplier" may be added. For a detailed description see above. Valid multipliers here are "b" (byte), "k" (kilobyte), "m" (megabyte), "g" (gigabyte), "t" (terabyte), and "p" (petabyte). Please note that there are 1000 bytes in a kilobyte, not 1024.

Recursive true|false

Controls whether or not to recurse into subdirectories. Enabled by default.

IncludeHidden true|false

Controls whether or not to include "hidden" files and directories in the count. "Hidden" files and directories are those, whose name begins with a dot. Defaults to false, i.e. by default hidden files and directories are ignored.

RegularOnly true|false

Controls whether or not to include only regular files in the count. Defaults to true, i.e. by default non regular files are ignored.

FilesSizeType Type

Sets the type used to dispatch files combined size. Empty value ("") disables reporting. Defaults to bytes.

FilesCountType Type

Sets the type used to dispatch number of files. Empty value ("") disables reporting. Defaults to files.

TypeInstance Instance

Sets the type instance used to dispatch values. Defaults to an empty string (no plugin instance).

### Plugin "GenericJMX"
The GenericJMX plugin is written in Java and therefore documented in collectd-java(5).

### Plugin "gmond"
The gmond plugin received the multicast traffic sent by gmond, the statistics collection daemon of Ganglia. Mappings for the standard "metrics" are built-in, custom mappings may be added via Metric blocks, see below.

Synopsis:

```
 <Plugin "gmond">
   MCReceiveFrom "239.2.11.71" "8649"
   <Metric "swap_total">
     Type "swap"
     TypeInstance "total"
     DataSource "value"
   </Metric>
   <Metric "swap_free">
     Type "swap"
     TypeInstance "free"
     DataSource "value"
   </Metric>
 </Plugin>
```

The following metrics are built-in:

- load_one, load_five, load_fifteen

- cpu_user, cpu_system, cpu_idle, cpu_nice, cpu_wio

- mem_free, mem_shared, mem_buffers, mem_cached, mem_total

- bytes_in, bytes_out

- pkts_in, pkts_out

Available configuration options:

MCReceiveFrom MCGroup [Port]

Sets sets the multicast group and UDP port to which to subscribe. Default: 239.2.11.71 / 8649

<Metric Name>

These blocks add a new metric conversion to the internal table. Name, the string argument to the Metric block, is the metric name as used by Ganglia.

Type Type

Type to map this metric to. Required.

TypeInstance Instance

Type-instance to use. Optional.

DataSource Name

Data source to map this metric to. If the configured type has exactly one data source, this is optional. Otherwise the option is required.

### Plugin "gps"
The "gps plugin" connects to gpsd on the host machine. The host, port, timeout and pause are configurable.

This is useful if you run an NTP server using a GPS for source and you want to monitor it.

Mind your GPS must send $--GSA for having the data reported!

The following elements are collected:

satellites

Number of satellites used for fix (type instance "used") and in view (type instance "visible"). 0 means no GPS satellites are visible.

dilution_of_precision

Vertical and horizontal dilution (type instance "horizontal" or "vertical"). It should be between 0 and 3. Look at the documentation of your GPS to know more.

Synopsis:

```
 LoadPlugin gps
 <Plugin "gps">
   # Connect to localhost on gpsd regular port:
   Host "127.0.0.1"
   Port "2947"
   # 15 ms timeout
   Timeout 0.015
   # PauseConnect of 5 sec. between connection attempts.
   PauseConnect 5
 </Plugin>
```

Available configuration options:

Host Host

The host on which gpsd daemon runs. Defaults to localhost.

Port Port

Port to connect to gpsd on the host machine. Defaults to 2947.

Timeout Seconds

Timeout in seconds (default 0.015 sec). The GPS data stream is fetch by the plugin form the daemon. It waits for data to be available, if none arrives it times out and loop for another reading. Mind to put a low value gpsd expects value in the micro-seconds area (recommended is 500 us) since the waiting function is blocking. Value must be between 500 us and 5 sec., if outside that range the default value is applied.

This only applies from gpsd release-2.95.

PauseConnect Seconds

Pause to apply between attempts of connection to gpsd in seconds (default 5 sec).

### Plugin "gpu_nvidia"
Efficiently collects various statistics from the system's NVIDIA GPUs using the NVML library. Currently collected are fan speed, core temperature, percent load, percent memory used, compute and memory frequencies, and power consumption.

GPUIndex

If one or more of these options is specified, only GPUs at that index (as determined by nvidia-utils through nvidia-smi) have statistics collected. If no instance of this option is specified, all GPUs are monitored.

IgnoreSelected

If set to true, all detected GPUs except the ones at indices specified by GPUIndex entries are collected. For greater clarity, setting IgnoreSelected without any GPUIndex directives will result in no statistics being collected.

InstanceByGPUIndex

If set to false, the GPU ID will not be part of the plugin instance. The default is 'GPU ID'-'GPU name'

InstanceByGPUName

If set to false, the GPU name will not be part of the plugin instance. The default is 'GPU ID'-'GPU name'

### Plugin "grpc"
The grpc plugin provides an RPC interface to submit values to or query values from collectd based on the open source gRPC framework. It exposes an end-point for dispatching values to the daemon.

The gRPC homepage can be found at <https://grpc.io/>.

Server Host Port

The Server statement sets the address of a server to which to send metrics via the "DispatchValues" function. The argument Host may be a hostname, an IPv4 address, or an IPv6 address.

Optionally, Server may be specified as a configuration block which supports the following options:

EnableSSL false|true

Whether to require SSL for outgoing connections. Default: false.

SSLCACertificateFile Filename

SSLCertificateFile Filename

SSLCertificateKeyFile Filename

Filenames specifying SSL certificate and key material to be used with SSL connections.

Listen Host Port

The Listen statement sets the network address to bind to. When multiple statements are specified, the daemon will bind to all of them. If none are specified, it defaults to 0.0.0.0:50051. The argument Host may be a hostname, an IPv4 address, or an IPv6 address.

Optionally, Listen may be specified as a configuration block which supports the following options:

EnableSSL true|false

Whether to enable SSL for incoming connections. Default: false.

SSLCACertificateFile Filename

SSLCertificateFile Filename

SSLCertificateKeyFile Filename

Filenames specifying SSL certificate and key material to be used with SSL connections.

VerifyPeer true|false

When enabled, a valid client certificate is required to connect to the server. When disabled, a client certifiacte is not requested and any unsolicited client certificate is accepted. Enabled by default.

### Plugin "hddtemp"
To get values from hddtemp collectd connects to localhost (127.0.0.1), port 7634/tcp. The Host and Port options can be used to change these default values, see below. "hddtemp" has to be running to work correctly. If "hddtemp" is not running timeouts may appear which may interfere with other statistics..

The hddtemp homepage can be found at <http://www.guzu.net/linux/hddtemp.php>.

Host Hostname

Hostname to connect to. Defaults to 127.0.0.1.

Port Port

TCP-Port to connect to. Defaults to 7634.

### Plugin "hugepages"
To collect hugepages information, collectd reads directories "/sys/devices/system/node/*/hugepages" and "/sys/kernel/mm/hugepages". Reading of these directories can be disabled by the following options (default is enabled).

ReportPerNodeHP true|false

If enabled, information will be collected from the hugepage counters in "/sys/devices/system/node/*/hugepages". This is used to check the per-node hugepage statistics on a NUMA system.

ReportRootHP true|false

If enabled, information will be collected from the hugepage counters in "/sys/kernel/mm/hugepages". This can be used on both NUMA and non-NUMA systems to check the overall hugepage statistics.

ValuesPages true|false

Whether to report hugepages metrics in number of pages. Defaults to true.

ValuesBytes false|true

Whether to report hugepages metrics in bytes. Defaults to false.

ValuesPercentage false|true

Whether to report hugepages metrics as percentage. Defaults to false.

### Plugin "infiniband"
The "infiniband" plugin collects information about IB ports. Metrics are gathered from "/sys/class/infiniband/DEVICE/port/PORTNUM/*", and Port names are formatted like "DEVICE:PORTNUM" (see examples below).

Options:

Port Port

Select the port Port. Whether it is collected or ignored depends on the IgnoreSelected setting, see below. As with other plugins that use the daemon's ignorelist functionality, a string that starts and ends with a slash is interpreted as a regular expression. Examples:

```
  Port "mlx5_0:1"
  Port "/mthca0:[0-9]/"

```

See /"IGNORELISTS" for details.

IgnoreSelected true|false

Sets whether selected ports are ignored or if all other ports are ignored. The behavior (hopefully) is intuitive: If no Port option is configured, all ports are collected. If at least one Port option is given and IgnoreSelected is not given or set to false, only matching ports will be collected. If IgnoreSelected is set to true, all ports are collected except the ones matched.

### Plugin "intel_pmu"
The intel_pmu plugin collects performance counters data on Intel CPUs using Linux perf interface. All events are reported on a per core basis.

Synopsis:

```
  <Plugin intel_pmu>
    ReportHardwareCacheEvents true
    ReportKernelPMUEvents true
    ReportSoftwareEvents true
    EventList "/var/cache/pmu/GenuineIntel-6-2D-core.json"
    HardwareEvents "L2_RQSTS.CODE_RD_HIT,L2_RQSTS.CODE_RD_MISS" "L2_RQSTS.ALL_CODE_RD"
    Cores "0-3" "4,6" "[12-15]"
    DispatchMultiPmu false
  </Plugin>
```

Options:

ReportHardwareCacheEvents false|true

Enable or disable measuring of hardware CPU cache events:

- L1-dcache-loads

- L1-dcache-load-misses

- L1-dcache-stores

- L1-dcache-store-misses

- L1-dcache-prefetches

- L1-dcache-prefetch-misses

- L1-icache-loads

- L1-icache-load-misses

- L1-icache-prefetches

- L1-icache-prefetch-misses

- LLC-loads

- LLC-load-misses

- LLC-stores

- LLC-store-misses

- LLC-prefetches

- LLC-prefetch-misses

- dTLB-loads

- dTLB-load-misses

- dTLB-stores

- dTLB-store-misses

- dTLB-prefetches

- dTLB-prefetch-misses

- iTLB-loads

- iTLB-load-misses

- branch-loads

- branch-load-misses

ReportKernelPMUEvents false|true

Enable or disable measuring of the following events:

- cpu-cycles

- instructions

- cache-references

- cache-misses

- branches

- branch-misses

- bus-cycles

ReportSoftwareEvents false|true

Enable or disable measuring of software events provided by kernel:

- cpu-clock

- task-clock

- context-switches

- cpu-migrations

- page-faults

- minor-faults

- major-faults

- alignment-faults

- emulation-faults

EventList filename

JSON performance counter event list file name. To be able to monitor all Intel CPU specific events JSON event list file should be downloaded. Use the pmu-tools event_download.py script to download event list for current CPU.

HardwareEvents events

This field is a list of event names or groups of comma separated event names. This option requires EventList option to be configured.

Cores cores groups

All events are reported on a per core basis. Monitoring of the events can be configured for a group of cores (aggregated statistics). This field defines groups of cores on which to monitor supported events. The field is represented as list of strings with core group values. Each string represents a list of cores in a group. If a group is enclosed in square brackets each core is added individually to a separate group (that is statistics are not aggregated). Allowed formats are:

0,1,2,3

0-10,20-18

1,3,5-8,10,0x10-12

[4-15,32-63] If an empty string is provided as value for this field default cores configuration is applied - that is separate group is created for each core.

DispatchMultiPmu false|true

Enable or disable dispatching of cloned multi PMU for uncore events. If disabled only total sum is dispatched as single event. If enabled separate metric is dispatched for every counter.

### Plugin "intel_rdt"
The intel_rdt plugin collects information provided by monitoring features of Intel Resource Director Technology (Intel(R) RDT) like Cache Monitoring Technology (CMT), Memory Bandwidth Monitoring (MBM). These features provide information about utilization of shared resources. CMT monitors last level cache occupancy (LLC). MBM supports two types of events reporting local and remote memory bandwidth. Local memory bandwidth (MBL) reports the bandwidth of accessing memory associated with the local socket. Remote memory bandwidth (MBR) reports the bandwidth of accessing the remote socket. Also this technology allows to monitor instructions per clock (IPC). Monitor events are hardware dependant. Monitoring capabilities are detected on plugin initialization and only supported events are monitored.

Note: intel_rdt plugin is using model-specific registers (MSRs), which require an additional capability to be enabled if collectd is run as a service. Please refer to contrib/systemd.collectd.service file for more details.

Synopsis:

```
  <Plugin "intel_rdt">
    Cores "0-2" "3,4,6" "8-10,15"
    Processes "sshd,qemu-system-x86" "bash"
  </Plugin>
```

Options:

Interval seconds

The interval within which to retrieve statistics on monitored events in seconds. For milliseconds divide the time by 1000 for example if the desired interval is 50ms, set interval to 0.05. Due to limited capacity of counters it is not recommended to set interval higher than 1 sec.

Cores cores groups

Monitoring of the events can be configured for group of cores (aggregated statistics). This field defines groups of cores on which to monitor supported events. The field is represented as list of strings with core group values. Each string represents a list of cores in a group. Allowed formats are:

0,1,2,3

0-10,20-18

1,3,5-8,10,0x10-12 If an empty string is provided as value for this field default cores configuration is applied - a separate group is created for each core.

Processes process names groups

Monitoring of the events can be configured for group of processes (aggregated statistics). This field defines groups of processes on which to monitor supported events. The field is represented as list of strings with process names group values. Each string represents a list of processes in a group. Allowed format is:

sshd,bash,qemu

Note: By default global interval is used to retrieve statistics on monitored events. To configure a plugin specific interval use Interval option of the intel_rdt <LoadPlugin> block. For milliseconds divide the time by 1000 for example if the desired interval is 50ms, set interval to 0.05. Due to limited capacity of counters it is not recommended to set interval higher than 1 sec.

### Plugin "interface"
Interface Interface

Select this interface. By default these interfaces will then be collected. For a more detailed description see IgnoreSelected below. See /"IGNORELISTS" for details.

IgnoreSelected true|false

If no configuration is given, the interface-plugin will collect data from all interfaces. This may not be practical, especially for loopback- and similar interfaces. Thus, you can use the Interface-option to pick the interfaces you're interested in. Sometimes, however, it's easier/preferred to collect all interfaces except a few ones. This option enables you to do that: By setting IgnoreSelected to true the effect of Interface is inverted: All selected interfaces are ignored and all other interfaces are collected. It is possible to use regular expressions to match interface names, if the name is surrounded by /.../ and collectd was compiled with support for regexps. This is useful if there's a need to collect (or ignore) data for a group of interfaces that are similarly named, without the need to explicitly list all of them (especially useful if the list is dynamic). Example:

```
 Interface "lo"
 Interface "/^veth/"
 Interface "/^tun[0-9]+/"
 IgnoreSelected "true"

```

This will ignore the loopback interface, all interfaces with names starting with veth and all interfaces with names starting with tun followed by at least one digit.

ReportInactive true|false

When set to false, only interfaces with non-zero traffic will be reported. Note that the check is done by looking into whether a package was sent at any time from boot and the corresponding counter is non-zero. So, if the interface has been sending data in the past since boot, but not during the reported time-interval, it will still be reported. The default value is true and results in collection of the data from all interfaces that are selected by Interface and IgnoreSelected options.

UniqueName true|false

Interface name is not unique on Solaris (KSTAT), interface name is unique only within a module/instance. Following tuple is considered unique:

(ks_module, ks_instance, ks_name) If this option is set to true, interface name contains above three fields separated by an underscore. For more info on KSTAT, visit <http://docs.oracle.com/cd/E23824_01/html/821-1468/kstat-3kstat.html#REFMAN3Ekstat-3kstat> This option is only available on Solaris.

### Plugin "ipmi"
The ipmi plugin allows to monitor server platform status using the Intelligent Platform Management Interface (IPMI). Local and remote interfaces are supported.

The plugin configuration consists of one or more Instance blocks which specify one ipmi connection each. Each block requires one unique string argument as the instance name. If instances are not configured, an instance with the default option values will be created.

For backwards compatibility, any option other than Instance block will trigger legacy config handling and it will be treated as an option within Instance block. This support will go away in the next major version of Collectd.

Within the Instance blocks, the following options are allowed:

Address Address

Hostname or IP to connect to. If not specified, plugin will try to connect to local management controller (BMC).

Username Username

Password Password

The username and the password to use for the connection to remote BMC.

AuthType MD5|rmcp+

Forces the authentication type to use for the connection to remote BMC. By default most secure type is seleted.

Host Hostname

Sets the host field of dispatched values. Defaults to the global hostname setting.

Sensor Sensor

Selects sensors to collect or to ignore, depending on IgnoreSelected. See /"IGNORELISTS" for details.

IgnoreSelected true|false

If no configuration if given, the ipmi plugin will collect data from all sensors found of type "temperature", "voltage", "current" and "fanspeed". This option enables you to do that: By setting IgnoreSelected to true the effect of Sensor is inverted: All selected sensors are ignored and all other sensors are collected.

NotifySensorAdd true|false

If a sensor appears after initialization time of a minute a notification is sent.

NotifySensorRemove true|false

If a sensor disappears a notification is sent.

NotifySensorNotPresent true|false

If you have for example dual power supply and one of them is (un)plugged then a notification is sent.

NotifyIPMIConnectionState true|false

If a IPMI connection state changes after initialization time of a minute a notification is sent. Defaults to false.

SELEnabled true|false

If system event log (SEL) is enabled, plugin will listen for sensor threshold and discrete events. When event is received the notification is sent. SEL event filtering can be configured using SELSensor and SELIgnoreSelected config options. Defaults to false.

SELSensor SELSensor

Selects sensors to get events from or to ignore, depending on SELIgnoreSelected. See /"IGNORELISTS" for details.

SELIgnoreSelected true|false

If no configuration is given, the ipmi plugin will pass events from all sensors. This option enables you to do that: By setting SELIgnoreSelected to true the effect of SELSensor is inverted: All events from selected sensors are ignored and all events from other sensors are passed.

SELClearEvent true|false

If SEL clear event is enabled, plugin will delete event from SEL list after it is received and successfully handled. In this case other tools that are subscribed for SEL events will receive an empty event. Defaults to false.

### Plugin "ipstats"
This plugin collects counts for ipv4 and ipv6 various types of packets passing through the system in total. At the moment it's only supported on FreeBSD.

The full list of options available to include in the counted statistics is:

ip4receive IPv4 total packets received

ip4badsum IPv4 checksum bad

ip4tooshort IPv4 packet too short

ip4toosmall IPv4 not enough data

ip4badhlen IPv4 ip header length < data size

ip4badlen IPv4 ip length < ip header length

ip4fragment IPv4 fragments received

ip4fragdrop IPv4 frags dropped (dups, out of space)

ip4fragtimeout IPv4 fragments timed out

ip4forward IPv4 packets forwarded

ip4fastforward IPv4 packets fast forwarded

ip4cantforward IPv4 packets rcvd for unreachable dest

ip4redirectsent IPv4 packets forwarded on same net

ip4noproto IPv4 unknown or unsupported protocol

ip4deliver IPv4 datagrams delivered to upper level

ip4transmit IPv4 total ip packets generated here

ip4odrop IPv4 lost packets due to nobufs, etc.

ip4reassemble IPv4 total packets reassembled ok

ip4fragmented IPv4 datagrams successfully fragmented

ip4ofragment IPv4 output fragments created

ip4cantfrag IPv4 don't fragment flag was set, etc.

ip4badoptions IPv4 error in option processing

ip4noroute IPv4 packets discarded due to no route

ip4badvers IPv4 ip version != 4

ip4rawout IPv4 total raw ip packets generated

ip4toolong IPv4 ip length > max ip packet size

ip4notmember IPv4 multicasts for unregistered grps

ip4nogif IPv4 no match gif found

ip4badaddr IPv4 invalid address on header

```
  ip6receive         IPv6 total packets received
  ip6tooshort        IPv6 packet too short
  ip6toosmall        IPv6 not enough data
  ip6fragment        IPv6 fragments received
  ip6fragdrop        IPv6 frags dropped(dups, out of space)
  ip6fragtimeout     IPv6 fragments timed out
  ip6fragoverflow    IPv6 fragments that exceeded limit
  ip6forward         IPv6 packets forwarded
  ip6cantforward     IPv6 packets rcvd for unreachable dest
  ip6redirectsent    IPv6 packets forwarded on same net
  ip6deliver         IPv6 datagrams delivered to upper level
  ip6transmit        IPv6 total ip packets generated here
  ip6odrop           IPv6 lost packets due to nobufs, etc.
  ip6reassemble      IPv6 total packets reassembled ok
  ip6fragmented      IPv6 datagrams successfully fragmented
  ip6ofragment       IPv6 output fragments created
  ip6cantfrag        IPv6 don't fragment flag was set, etc.
  ip6badoptions      IPv6 error in option processing
  ip6noroute         IPv6 packets discarded due to no route
  ip6badvers         IPv6 ip6 version != 6
  ip6rawout          IPv6 total raw ip packets generated
  ip6badscope        IPv6 scope error
  ip6notmember       IPv6 don't join this multicast group
  ip6nogif           IPv6 no match gif found
  ip6toomanyhdr      IPv6 discarded due to too many headers
```

By default the following options are included in the counted packets:

- ip4receive - ip4forward - ip4transmit

- ip6receive - ip6forward - ip6transmit

For example to also count IPv4 and IPv6 fragments received, include the following configuration:

```
  <Plugin ipstats>
    ip4fragment true
    ip6fragment true
  </Plugin>
```

### Plugin "iptables"
Chain Table Chain [Comment|Number [Name]]

Chain6 Table Chain [Comment|Number [Name]]

Select the iptables/ip6tables filter rules to count packets and bytes from. If only Table and Chain are given, this plugin will collect the counters of all rules which have a comment-match. The comment is then used as type-instance.

If Comment or Number is given, only the rule with the matching comment or the nth rule will be collected. Again, the comment (or the number) will be used as the type-instance.

If Name is supplied, it will be used as the type-instance instead of the comment or the number.

### Plugin "irq"
Irq Irq

Select this irq. By default these irqs will then be collected. For a more detailed description see IgnoreSelected below. See /"IGNORELISTS" for details.

IgnoreSelected true|false

If no configuration if given, the irq-plugin will collect data from all irqs. This may not be practical, especially if no interrupts happen. Thus, you can use the Irq-option to pick the interrupt you're interested in. Sometimes, however, it's easier/preferred to collect all interrupts except a few ones. This option enables you to do that: By setting IgnoreSelected to true the effect of Irq is inverted: All selected interrupts are ignored and all other interrupts are collected.

### Plugin "java"
The Java plugin makes it possible to write extensions for collectd in Java. This section only discusses the syntax and semantic of the configuration options. For more in-depth information on the Java plugin, please read collectd-java(5).

Synopsis:

```
 <Plugin "java">
   JVMArg "-verbose:jni"
   JVMArg "-Djava.class.path=/opt/collectd/lib/collectd/bindings/java"
   LoadPlugin "org.collectd.java.Foobar"
   <Plugin "org.collectd.java.Foobar">
     # To be parsed by the plugin
   </Plugin>
 </Plugin>
```

Available configuration options:

JVMArg Argument

Argument that is to be passed to the Java Virtual Machine (JVM). This works exactly the way the arguments to the java binary on the command line work. Execute "java --help" for details. Please note that all these options must appear before (i. e. above) any other options! When another option is found, the JVM will be started and later options will have to be ignored!

LoadPlugin JavaClass

Instantiates a new JavaClass object. The constructor of this object very likely then registers one or more callback methods with the server. See collectd-java(5) for details.

When the first such option is found, the virtual machine (JVM) is created. This means that all JVMArg options must appear before (i. e. above) all LoadPlugin options!

Plugin Name

The entire block is passed to the Java plugin as an org.collectd.api.OConfigItem object. For this to work, the plugin has to register a configuration callback first, see "config callback" in collectd-java(5). This means, that the Plugin block must appear after the appropriate LoadPlugin block. Also note, that Name depends on the (Java) plugin registering the callback and is completely independent from the JavaClass argument passed to LoadPlugin.

### Plugin "load"
The Load plugin collects the system load. These numbers give a rough overview over the utilization of a machine. The system load is defined as the number of runnable tasks in the run-queue and is provided by many operating systems as a one, five or fifteen minute average.

The following configuration options are available:

ReportRelative false|true

When enabled, system load divided by number of available CPU cores is reported for intervals 1 min, 5 min and 15 min. Defaults to false.

### Plugin "logfile"
LogLevel debug|info|notice|warning|err

Sets the log-level. If, for example, set to notice, then all events with severity notice, warning, or err will be written to the logfile. Please note that debug is only available if collectd has been compiled with debugging support.

File File

Sets the file to write log messages to. The special strings stdout and stderr can be used to write to the standard output and standard error channels, respectively. This, of course, only makes much sense when collectd is running in foreground- or non-daemon-mode.

Timestamp true|false

Prefix all lines printed by the current time. Defaults to true.

PrintSeverity true|false

When enabled, all lines are prefixed by the severity of the log message, for example "warning". Defaults to false.

Note: There is no need to notify the daemon after moving or removing the log file (e. g. when rotating the logs). The plugin reopens the file for each line it writes.

### Plugin "logparser"
The logparser plugin is used to parse different kinds of logs. Setting proper options you can choose strings to collect. Plugin searches the log file for messages which contain several matches (two or more). When all mandatory matches are found then it sends proper notification containing all fetched values.

Synopsis:

```
  <Plugin logparser>
    <Logfile "/var/log/syslog">
      FirstFullRead false
      <Message "pcie_errors">
        DefaultType "pcie_error"
        DefaultSeverity "warning"
        <Match "aer error">
          Regex "AER:.*error received"
          SubmatchIdx -1
        </Match>
        <Match "incident time">
          Regex "(... .. ..:..:..) .* pcieport.*AER"
          SubmatchIdx 1
          IsMandatory false
        </Match>
        <Match "root port">
          Regex "pcieport (.*): AER:"
          SubmatchIdx 1
          IsMandatory true
        </Match>
        <Match "device">
          PluginInstance true
          Regex " ([0-9a-fA-F:\\.]*): PCIe Bus Error"
          SubmatchIdx 1
          IsMandatory false
        </Match>
        <Match "severity_mandatory">
          Regex "severity="
          SubMatchIdx -1
        </Match>
        <Match "nonfatal">
          Regex "severity=.*\\([nN]on-[fF]atal"
          TypeInstance "non_fatal"
          IsMandatory false
        </Match>
        <Match "fatal">
          Regex "severity=.*\\([fF]atal"
          Severity "failure"
          TypeInstance "fatal"
          IsMandatory false
        </Match>
        <Match "corrected">
          Regex "severity=Corrected"
          TypeInstance "correctable"
          IsMandatory false
        </Match>
        <Match "error type">
          Regex "type=(.*),"
          SubmatchIdx 1
          IsMandatory false
        </Match>
       <Match "id">
          Regex ", id=(.*)"
          SubmatchIdx 1
        </Match>
      </Message>
    </Logfile>
  </Plugin>
```

Options:

Logfile File

The Logfile block defines file to search. It may contain one or more Message blocks which are defined below.

FirstFullRead true|false

Set to true if the file has to be parsed from the beginning on the first read. If false only subsequent writes to log file will be parsed.

Message Name

Message block contains matches to search the log file for. Each Message block builds a notification message using matched elements if its mandatory Match blocks are matched.

DefaultPluginInstance String

Sets the default value for the plugin instance of the notification.

DefaultType String

Sets the default value for the type of the notification.

DefaultTypeInstance String

Sets the default value for the type instance of the notification.

DefaultSeverity String

Sets the default severity. Must be set to "OK", "WARNING" or "FAILURE". Default value is "OK".

Match Name

Multiple Match blocks define regular expression patterns for extracting or excluding specific string patterns from parsing. First and last Match items in the same Message set boundaries of multiline message and are mandatory. If these matches are not found then the whole message is discarded.

Regex Regex

Regular expression with pattern matching string. It may contain subexpressions, so next option SubmatchIdx specifies which subexpression should be stored.

SubmatchIdx Integer

Index of subexpression to be used for notification. Multiple subexpressions are allowed. Index value 0 takes whole regular expression match as a result. Index value -1 does not add result to message item. Can be omitted, default value is 0.

Excluderegex Regex

Regular expression for excluding lines containing specific matching strings. This is processed before checking Regex pattern. It is optional and can be omitted.

IsMandatory true|false

Flag indicating if Match item is mandatory for message validation. If set to true, whole message is discarded if it's missing. For false its presence is optional. Default value is set to true.

PluginInstance true|String

If set to true, it sets plugin instance to string returned by regex. It can be overridden by user string.

Type true|String

Sets notification type using rules like PluginInstance.

TypeInstance true|String

Sets notification type instance using rules like above.

Severity String

Sets notification severity to one of the options: "OK", "WARNING", "FAILURE".

### Plugin "log_logstash"
The log logstash plugin behaves like the logfile plugin but formats messages as JSON events for logstash to parse and input.

LogLevel debug|info|notice|warning|err

Sets the log-level. If, for example, set to notice, then all events with severity notice, warning, or err will be written to the logfile. Please note that debug is only available if collectd has been compiled with debugging support.

File File

Sets the file to write log messages to. The special strings stdout and stderr can be used to write to the standard output and standard error channels, respectively. This, of course, only makes much sense when collectd is running in foreground- or non-daemon-mode.

Note: There is no need to notify the daemon after moving or removing the log file (e. g. when rotating the logs). The plugin reopens the file for each line it writes.

### Plugin "lpar"
The LPAR plugin reads CPU statistics of Logical Partitions, a virtualization technique for IBM POWER processors. It takes into account CPU time stolen from or donated to a partition, in addition to the usual user, system, I/O statistics.

The following configuration options are available:

CpuPoolStats false|true

When enabled, statistics about the processor pool are read, too. The partition needs to have pool authority in order to be able to acquire this information. Defaults to false.

ReportBySerial false|true

If enabled, the serial of the physical machine the partition is currently running on is reported as hostname and the logical hostname of the machine is reported in the plugin instance. Otherwise, the logical hostname will be used (just like other plugins) and the plugin instance will be empty. Defaults to false.

### Plugin "lua"
This plugin embeds a Lua interpreter into collectd and provides an interface to collectd's plugin system. See collectd-lua(5) for its documentation.

### Plugin "mbmon"
The "mbmon plugin" uses mbmon to retrieve temperature, voltage, etc.

Be default collectd connects to localhost (127.0.0.1), port 411/tcp. The Host and Port options can be used to change these values, see below. "mbmon" has to be running to work correctly. If "mbmon" is not running timeouts may appear which may interfere with other statistics..

"mbmon" must be run with the -r option ("print TAG and Value format"); Debian's /etc/init.d/mbmon script already does this, other people will need to ensure that this is the case.

Host Hostname

Hostname to connect to. Defaults to 127.0.0.1.

Port Port

TCP-Port to connect to. Defaults to 411.

### Plugin "mdevents "
The mdevents plugin collects status changes from md (Linux software RAID) devices.

RAID arrays are meant to allow users/administrators to keep systems up and running, in case of common hardware problems (disk failure). Mdadm is the standard software RAID management tool for Linux. It provides the ability to monitor "metadata event" occurring such as disk failures, clean-to-dirty transitions, and etc. The kernel provides the ability to report such actions to the userspace via sysfs, and mdadm takes action accordingly with the monitoring capability. The mdmon polls the /sys looking for changes in the entries array_state, sync_action, and per disk state attribute files. This is meaningful for RAID1, 5 and 10 only.

Mdevents plugin is based on gathering RAID array events that are written to syslog by mdadm. After registering an event, it can send a collectd notification that contains mdadm event's data. Event consists of event type, raid array name and, for particular events, name of component device.

Example message:

"Jan 17 05:24:27 pc1 mdadm[188]: NewArray event detected on md device /dev/md0"

Plugin also classifies gathered event. This means that a notification will have a different severity {OKAY, WARNING, FAILURE} for particular mdadm event.

For proper work, mdevents plugin needs syslog and mdadm utilities to be present on the running system. Otherwise it will not be compiled as a part of collectd.

Synopsis:

```
  <Plugin mdevents>
    Event ""
    IgnoreEvent False
    Array ""
    IgnoreArray False
  </Plugin>
```

Plugin configuration:

Mdevents plugin's configuration is mostly based on IgnoreList, which is a collectd's utility. User can specify what particular events/RAID arrays lie in his interest. Setting of IgnoreEvent/IgnoreArray booleans won't take effect if Event/Array config lists are empty - plugin will accept entry anyway.

Options:

Event "EventName"

Names of events to be monitored, separated by spaces. Possible events include: Event Name | Class of event ------------------+--------------- DeviceDisappeared | FAILURE RebuildStarted | OKAY RebuildNN | OKAY RebuildFinished | WARNING Fail | FAILURE FailSpare | WARNING SpareActive | OKAY NewArray | OKAY DegradedArray | FAILURE MoveSpare | WARNING SparesMissing | WARNING TestMessage | OKAY

User should set the events that should be monitored as a strings separated by spaces, for example Events "DeviceDisappeared Fail DegradedArray".

IgnoreEvent false|true

If IgnoreEvent is set to true, events specified in Events will be ignored. If it's false, only specified events will be monitored.

Array arrays

User can specify an array or a group of arrays using regexp. Plugin will accept only RAID arrays names that start with "/dev/md".

IgnoreArray false|true

If IgnoreArray is set to true, arrays specified in Array will be ignored. If it's false, only specified events will be monitored.

### Plugin "mcelog"
The "mcelog plugin" uses mcelog to retrieve machine check exceptions.

By default the plugin connects to "/var/run/mcelog-client" to check if the mcelog server is running. When the server is running, the plugin will tail the specified logfile to retrieve machine check exception information and send a notification with the details from the logfile. The plugin will use the mcelog client protocol to retrieve memory related machine check exceptions. Note that for memory exceptions, notifications are only sent when there is a change in the number of corrected/uncorrected memory errors.

The Memory block

Note: these options cannot be used in conjunction with the logfile options, they are mutually exclusive.

McelogClientSocket Path Connect to the mcelog client socket using the UNIX domain socket at Path. Defaults to "/var/run/mcelog-client".

PersistentNotification true|false Override default configuration to only send notifications when sent when there is a change in the number of corrected/uncorrected memory errors. When set to true notifications will be sent for every read cycle. Default is false. Does not affect the stats being dispatched.

McelogLogfile Path

The mcelog file to parse. Defaults to "/var/log/mcelog". Note: this option cannot be used in conjunction with the memory block options, they are mutually exclusive.

### Plugin "md"
The "md plugin" collects information from Linux Software-RAID devices (md).

All reported values are of the type "md_disks". Reported type instances are active, failed (present but not operational), spare (hot stand-by) and missing (physically absent) disks.

Device Device

Select md devices based on device name. The device name is the basename of the device, i.e. the name of the block device without the leading "/dev/". See IgnoreSelected for more details. See /"IGNORELISTS" for details.

IgnoreSelected true|false

Invert device selection: If set to true, all md devices except those listed using Device are collected. If false (the default), only those listed are collected. If no configuration is given, the md plugin will collect data from all md devices.

### Plugin "memcachec"
The "memcachec plugin" connects to a memcached server, queries one or more given pages and parses the returned data according to user specification. The matches used are the same as the matches used in the "curl" and "tail" plugins.

In order to talk to the memcached server, this plugin uses the libmemcached library. Please note that there is another library with a very similar name, libmemcache (notice the missing `d'), which is not applicable.

Synopsis of the configuration:

```
 <Plugin "memcachec">
   <Page "plugin_instance">
     Server "localhost"
     Key "page_key"
     Plugin "plugin_name"
     <Match>
       Regex "(\\d+) bytes sent"
       DSType CounterAdd
       Type "ipt_octets"
       Instance "type_instance"
     </Match>
   </Page>
 </Plugin>
```

The configuration options are:

<Page Name>

Each Page block defines one page to be queried from the memcached server. The block requires one string argument which is used as plugin instance.

Server Address

Sets the server address to connect to when querying the page. Must be inside a Page block.

Key Key

When connected to the memcached server, asks for the page Key.

Plugin Plugin

Use Plugin as the plugin name when submitting values. Defaults to "memcachec".

<Match>

Match blocks define which strings to look for and how matches substrings are interpreted. For a description of match blocks, please see "Plugin tail".

### Plugin "memcached"
The memcached plugin connects to a memcached server and queries statistics about cache utilization, memory and bandwidth used. <http://memcached.org/>

```
 <Plugin "memcached">
   <Instance "name">
     #Host "memcache.example.com"
     Address "127.0.0.1"
     Port 11211
   </Instance>
 </Plugin>
```

The plugin configuration consists of one or more Instance blocks which specify one memcached connection each. Within the Instance blocks, the following options are allowed:

Host Hostname

Sets the host field of dispatched values. Defaults to the global hostname setting. For backwards compatibility, values are also dispatched with the global hostname when Host is set to 127.0.0.1 or localhost and Address is not set.

Address Address

Hostname or IP to connect to. For backwards compatibility, defaults to the value of Host or 127.0.0.1 if Host is unset.

Port Port

TCP port to connect to. Defaults to 11211.

Socket Path

Connect to memcached using the UNIX domain socket at Path. If this setting is given, the Address and Port settings are ignored.

### Plugin "mic"
The mic plugin gathers CPU statistics, memory usage and temperatures from Intel's Many Integrated Core (MIC) systems.

Synopsis:

```
 <Plugin mic>
   ShowCPU true
   ShowCPUCores true
   ShowMemory true
   ShowTemperatures true
   Temperature vddg
   Temperature vddq
   IgnoreSelectedTemperature true
   ShowPower true
   Power total0
   Power total1
   IgnoreSelectedPower true
 </Plugin>
```

The following options are valid inside the Plugin mic block:

ShowCPU true|false

If enabled (the default) a sum of the CPU usage across all cores is reported.

ShowCPUCores true|false

If enabled (the default) per-core CPU usage is reported.

ShowMemory true|false

If enabled (the default) the physical memory usage of the MIC system is reported.

ShowTemperatures true|false

If enabled (the default) various temperatures of the MIC system are reported.

Temperature Name

This option controls which temperatures are being reported. Whether matching temperatures are being ignored or only matching temperatures are reported depends on the IgnoreSelectedTemperature setting below. By default all temperatures are reported.

IgnoreSelectedTemperature false|true

Controls the behavior of the Temperature setting above. If set to false (the default) only temperatures matching a Temperature option are reported or, if no Temperature option is specified, all temperatures are reported. If set to true, matching temperatures are ignored and all other temperatures are reported. Known temperature names are:

die

Die of the CPU

devmem

Device Memory

fin

Fan In

fout

Fan Out

vccp

Voltage ccp

vddg

Voltage ddg

vddq

Voltage ddq

ShowPower true|false

If enabled (the default) various temperatures of the MIC system are reported.

Power Name

This option controls which power readings are being reported. Whether matching power readings are being ignored or only matching power readings are reported depends on the IgnoreSelectedPower setting below. By default all power readings are reported.

IgnoreSelectedPower false|true

Controls the behavior of the Power setting above. If set to false (the default) only power readings matching a Power option are reported or, if no Power option is specified, all power readings are reported. If set to true, matching power readings are ignored and all other power readings are reported. Known power names are:

total0

Total power utilization averaged over Time Window 0 (uWatts).

total1

Total power utilization averaged over Time Window 0 (uWatts).

inst

Instantaneous power (uWatts).

imax

Max instantaneous power (uWatts).

pcie

PCI-E connector power (uWatts).

c2x3

2x3 connector power (uWatts).

c2x4

2x4 connector power (uWatts).

vccp

Core rail (uVolts).

vddg

Uncore rail (uVolts).

vddq

Memory subsystem rail (uVolts).

### Plugin "memory"
The memory plugin provides the following configuration options:

ValuesAbsolute true|false

Enables or disables reporting of physical memory usage in absolute numbers, i.e. bytes. Defaults to true.

ValuesPercentage false|true

Enables or disables reporting of physical memory usage in percentages, e.g. percent of physical memory used. Defaults to false. This is useful for deploying collectd in a heterogeneous environment in which the sizes of physical memory vary.

### Plugin "modbus"
The modbus plugin connects to a Modbus "slave" via Modbus/TCP or Modbus/RTU and reads register values. It supports reading single registers (unsigned 16 bit values), large integer values (unsigned 32 bit and 64 bit values) and floating point values (two registers interpreted as IEEE floats in big endian notation).

Synopsis:

```
 <Data "voltage-input-1">
   RegisterBase 0
   RegisterType float
   RegisterCmd ReadHolding
   Type voltage
   Instance "input-1"
   #Scale 1.0
   #Shift 0.0
 </Data>
 <Data "voltage-input-2">
   RegisterBase 2
   RegisterType float
   RegisterCmd ReadHolding
   Type voltage
   Instance "input-2"
 </Data>
 <Data "supply-temperature-1">
   RegisterBase 0
   RegisterType Int16
   RegisterCmd ReadHolding
   Type temperature
   Instance "temp-1"
 </Data>
 <Host "modbus.example.com">
   Address "192.168.0.42"
   Port    "502"
   Interval 60
   <Slave 1>
     Instance "power-supply"
     Collect  "voltage-input-1"
     Collect  "voltage-input-2"
   </Slave>
 </Host>
 <Host "localhost">
   Device "/dev/ttyUSB0"
   Baudrate 38400
   Interval 20
   <Slave 1>
     Instance "temperature"
     Collect  "supply-temperature-1"
   </Slave>
 </Host>
```

<Data Name> blocks

Data blocks define a mapping between register numbers and the "types" used by collectd. Within <Data /> blocks, the following options are allowed:

RegisterBase Number

Configures the base register to read from the device. If the option RegisterType has been set to Uint32 or Float, this and the next register will be read (the register number is increased by one).

RegisterType Int16|Int32|Int64|Uint16|Uint32|UInt64|Float|Int32LE|Uint32LE|FloatLE

Specifies what kind of data is returned by the device. This defaults to Uint16. If the type is Int32, Int32LE, Uint32, Uint32LE, Float or FloatLE, two 16 bit registers at RegisterBase and RegisterBase+1 will be read and the data is combined into one 32 value. For Int32, Uint32 and Float the most significant 16 bits are in the register at RegisterBase and the least significant 16 bits are in the register at RegisterBase+1. For Int32LE, Uint32LE, or Float32LE, the high and low order registers are swapped with the most significant 16 bits in the RegisterBase+1 and the least significant 16 bits in RegisterBase. If the type is Int64 or UInt64, four 16 bit registers at RegisterBase, RegisterBase+1, RegisterBase+2 and RegisterBase+3 will be read and the data combined into one 64 value.

RegisterCmd ReadHolding|ReadInput

Specifies register type to be collected from device. Works only with libmodbus 2.9.2 or higher. Defaults to ReadHolding.

Type Type

Specifies the "type" (data set) to use when dispatching the value to collectd. Currently, only data sets with exactly one data source are supported.

Instance Instance

Sets the type instance to use when dispatching the value to Instance. If unset, an empty string (no type instance) is used.

Scale Value

The values taken from device are multiplied by Value. The field is optional and the default is 1.0.

Shift Value

Value is added to values from device after they have been multiplied by Scale value. The field is optional and the default value is 0.0.

<Host Name> blocks

Host blocks are used to specify to which hosts to connect and what data to read from their "slaves". The string argument Name is used as hostname when dispatching the values to collectd. Within <Host /> blocks, the following options are allowed:

Address Hostname

For Modbus/TCP, specifies the node name (the actual network address) used to connect to the host. This may be an IP address or a hostname. Please note that the used libmodbus library only supports IPv4 at the moment.

Port Service

for Modbus/TCP, specifies the port used to connect to the host. The port can either be given as a number or as a service name. Please note that the Service argument must be a string, even if ports are given in their numerical form. Defaults to "502".

Device Devicenode

For Modbus/RTU, specifies the path to the serial device being used.

Baudrate Baudrate

For Modbus/RTU, specifies the baud rate of the serial device. Note, connections currently support only 8/N/1.

UARTType UARTType

For Modbus/RTU, specifies the type of the serial device. RS232, RS422 and RS485 are supported. Defaults to RS232. Available only on Linux systems with libmodbus>=2.9.4.

Interval Interval

Sets the interval (in seconds) in which the values will be collected from this host. By default the global Interval setting will be used.

<Slave ID>

Over each connection, multiple Modbus devices may be reached. The slave ID is used to specify which device should be addressed. For each device you want to query, one Slave block must be given. Within <Slave /> blocks, the following options are allowed:

Instance Instance

Specify the plugin instance to use when dispatching the values to collectd. By default "slave_ID" is used.

Collect DataName

Specifies which data to retrieve from the device. DataName must be the same string as the Name argument passed to a Data block. You can specify this option multiple times to collect more than one value from a slave. At least one Collect option is mandatory.

### Plugin "mqtt"
The MQTT plugin can send metrics to MQTT (Publish blocks) and receive values from MQTT (Subscribe blocks).

Synopsis:

```
 <Plugin mqtt>
   <Publish "name">
     Host "mqtt.example.com"
     Prefix "collectd"
   </Publish>
   <Subscribe "name">
     Host "mqtt.example.com"
     Topic "collectd/#"
   </Subscribe>
 </Plugin>
```

The plugin's configuration is in Publish and/or Subscribe blocks, configuring the sending and receiving direction respectively. The plugin will register a write callback named "mqtt/name" where name is the string argument given to the Publish block. Both types of blocks share many but not all of the following options. If an option is valid in only one of the blocks, it will be mentioned explicitly.

Options:

Host Hostname

Hostname of the MQTT broker to connect to.

Port Service

Port number or service name of the MQTT broker to connect to.

User UserName

Username used when authenticating to the MQTT broker.

Password Password

Password used when authenticating to the MQTT broker.

ClientId ClientId

MQTT client ID to use. Defaults to the hostname used by collectd.

QoS [0-2]

Sets the Quality of Service, with the values 0, 1 and 2 meaning:

0

At most once

1

At least once

2

Exactly once

In Publish blocks, this option determines the QoS flag set on outgoing messages and defaults to 0. In Subscribe blocks, determines the maximum QoS setting the client is going to accept and defaults to 2. If the QoS flag on a message is larger than the maximum accepted QoS of a subscriber, the message's QoS will be downgraded.

Prefix Prefix (Publish only)

This plugin will use one topic per value list which will looks like a path. Prefix is used as the first path element and defaults to collectd. An example topic name would be:

```
 collectd/cpu-0/cpu-user

```

Retain false|true (Publish only)

Controls whether the MQTT broker will retain (keep a copy of) the last message sent to each topic and deliver it to new subscribers. Defaults to false.

StoreRates true|false (Publish only)

Controls whether "DERIVE" and "COUNTER" metrics are converted to a rate before sending. Defaults to true.

CleanSession true|false (Subscribe only)

Controls whether the MQTT "cleans" the session up after the subscriber disconnects or if it maintains the subscriber's subscriptions and all messages that arrive while the subscriber is disconnected. Defaults to true.

Topic TopicName (Subscribe only)

Configures the topic(s) to subscribe to. You can use the single level "+" and multi level "#" wildcards. Defaults to collectd/#, i.e. all topics beneath the collectd branch.

CACert file

Path to the PEM-encoded CA certificate file. Setting this option enables TLS communication with the MQTT broker, and as such, Port should be the TLS-enabled port of the MQTT broker. This option enables the use of TLS.

CertificateFile file

Path to the PEM-encoded certificate file to use as client certificate when connecting to the MQTT broker. Only valid if CACert and CertificateKeyFile are also set.

CertificateKeyFile file

Path to the unencrypted PEM-encoded key file corresponding to CertificateFile. Only valid if CACert and CertificateFile are also set.

TLSProtocol protocol

If configured, this specifies the string protocol version (e.g. "tlsv1", "tlsv1.2") to use for the TLS connection to the broker. If not set a default version is used which depends on the version of OpenSSL the Mosquitto library was linked against. Only valid if CACert is set.

CipherSuite ciphersuite

A string describing the ciphers available for use. See ciphers(1) and the "openssl ciphers" utility for more information. If unset, the default ciphers will be used. Only valid if CACert is set.

### Plugin "mysql"
The "mysql plugin" requires mysqlclient to be installed. It connects to one or more databases when started and keeps the connection up as long as possible. When the connection is interrupted for whatever reason it will try to re-connect. The plugin will complain loudly in case anything goes wrong.

This plugin issues the MySQL "SHOW STATUS" / "SHOW GLOBAL STATUS" command and collects information about MySQL network traffic, executed statements, requests, the query cache and threads by evaluating the "Bytes_{received,sent}", "Com_*", "Handler_*", "Qcache_*" and "Threads_*" return values. Please refer to the MySQL reference manual, 5.1.6. Server Status Variables for an explanation of these values.

Optionally, master and slave statistics may be collected in a MySQL replication setup. In that case, information about the synchronization state of the nodes are collected by evaluating the "Position" return value of the "SHOW MASTER STATUS" command and the "Seconds_Behind_Master", "Read_Master_Log_Pos" and "Exec_Master_Log_Pos" return values of the "SHOW SLAVE STATUS" command. See the MySQL reference manual, 12.5.5.21 SHOW MASTER STATUS Syntax and 12.5.5.31 SHOW SLAVE STATUS Syntax for details.

Synopsis:

```
  <Plugin mysql>
    <Database foo>
      Host "hostname"
      User "username"
      Password "password"
      Port "3306"
      MasterStats true
      ConnectTimeout 10
      SSLKey "/path/to/key.pem"
      SSLCert "/path/to/cert.pem"
      SSLCA "/path/to/ca.pem"
      SSLCAPath "/path/to/cas/"
      SSLCipher "DHE-RSA-AES256-SHA"
    </Database>
    <Database bar>
      Alias "squeeze"
      Host "localhost"
      Socket "/var/run/mysql/mysqld.sock"
      SlaveStats true
      SlaveNotifications true
    </Database>
   <Database galera>
      Alias "galera"
      Host "localhost"
      Socket "/var/run/mysql/mysqld.sock"
      WsrepStats true
   </Database>
  </Plugin>
```

A Database block defines one connection to a MySQL database. It accepts a single argument which specifies the name of the database. None of the other options are required. MySQL will use default values as documented in the "mysql_real_connect()" and "mysql_ssl_set()" sections in the MySQL reference manual.

Alias Alias

Alias to use as sender instead of hostname when reporting. This may be useful when having cryptic hostnames.

Host Hostname

Hostname of the database server. Defaults to localhost.

User Username

Username to use when connecting to the database. The user does not have to be granted any privileges (which is synonym to granting the "USAGE" privilege), unless you want to collect replication statistics (see MasterStats and SlaveStats below). In this case, the user needs the "REPLICATION CLIENT" (or "SUPER") privileges. Else, any existing MySQL user will do.

Password Password

Password needed to log into the database.

Database Database

Select this database. Defaults to no database which is a perfectly reasonable option for what this plugin does.

Port Port

TCP-port to connect to. The port must be specified in its numeric form, but it must be passed as a string nonetheless. For example:

```
  Port "3306"

```

If Host is set to localhost (the default), this setting has no effect. See the documentation for the "mysql_real_connect" function for details.

Socket Socket

Specifies the path to the UNIX domain socket of the MySQL server. This option only has any effect, if Host is set to localhost (the default). Otherwise, use the Port option above. See the documentation for the "mysql_real_connect" function for details.

InnodbStats true|false

If enabled, metrics about the InnoDB storage engine are collected. Disabled by default.

MasterStats true|false

SlaveStats true|false

Enable the collection of master / slave statistics in a replication setup. In order to be able to get access to these statistics, the user needs special privileges. See the User documentation above. Defaults to false.

SlaveNotifications true|false

If enabled, the plugin sends a notification if the replication slave I/O and / or SQL threads are not running. Defaults to false.

WsrepStats true|false

Enable the collection of wsrep plugin statistics, used in Master-Master replication setups like in MySQL Galera/Percona XtraDB Cluster. User needs only privileges to execute 'SHOW GLOBAL STATUS'. Defaults to false.

ConnectTimeout Seconds

Sets the connect timeout for the MySQL client.

SSLKey Path

If provided, the X509 key in PEM format.

SSLCert Path

If provided, the X509 cert in PEM format.

SSLCA Path

If provided, the CA file in PEM format (check OpenSSL docs).

SSLCAPath Path

If provided, the CA directory (check OpenSSL docs).

SSLCipher String

If provided, the SSL cipher to use.

### Plugin "netapp"
The netapp plugin can collect various performance and capacity information from a NetApp filer using the NetApp API.

Please note that NetApp has a wide line of products and a lot of different software versions for each of these products. This plugin was developed for a NetApp FAS3040 running OnTap 7.2.3P8 and tested on FAS2050 7.3.1.1L1, FAS3140 7.2.5.1 and FAS3020 7.2.4P9. It should work for most combinations of model and software version but it is very hard to test this. If you have used this plugin with other models and/or software version, feel free to send us a mail to tell us about the results, even if it's just a short "It works".

To collect these data collectd will log in to the NetApp via HTTP(S) and HTTP basic authentication.

Do not use a regular user for this! Create a special collectd user with just the minimum of capabilities needed. The user only needs the "login-http-admin" capability as well as a few more depending on which data will be collected. Required capabilities are documented below.

Synopsis

```
 <Plugin "netapp">
   <Host "netapp1.example.com">
    Protocol      "https"
    Address       "10.0.0.1"
    Port          443
    User          "username"
    Password      "aef4Aebe"
    Interval      30
    <WAFL>
      Interval 30
      GetNameCache   true
      GetDirCache    true
      GetBufferCache true
      GetInodeCache  true
    </WAFL>
    <Disks>
      Interval 30
      GetBusy true
    </Disks>
    <VolumePerf>
      Interval 30
      GetIO      "volume0"
      IgnoreSelectedIO      false
      GetOps     "volume0"
      IgnoreSelectedOps     false
      GetLatency "volume0"
      IgnoreSelectedLatency false
    </VolumePerf>
    <VolumeUsage>
      Interval 30
      GetCapacity "vol0"
      GetCapacity "vol1"
      IgnoreSelectedCapacity false
      GetSnapshot "vol1"
      GetSnapshot "vol3"
      IgnoreSelectedSnapshot false
    </VolumeUsage>
    <Quota>
      Interval 60
    </Quota>
    <Snapvault>
      Interval 30
    </Snapvault>
    <System>
      Interval 30
      GetCPULoad     true
      GetInterfaces  true
      GetDiskOps     true
      GetDiskIO      true
    </System>
    <VFiler vfilerA>
      Interval 60
      SnapVault true
      # ...
    </VFiler>
   </Host>
 </Plugin>
```

The netapp plugin accepts the following configuration options:

Host Name

A host block defines one NetApp filer. It will appear in collectd with the name you specify here which does not have to be its real name nor its hostname (see the Address option below).

VFiler Name

A VFiler block may only be used inside a host block. It accepts all the same options as the Host block (except for cascaded VFiler blocks) and will execute all NetApp API commands in the context of the specified VFiler(R). It will appear in collectd with the name you specify here which does not have to be its real name. The VFiler name may be specified using the VFilerName option. If this is not specified, it will default to the name you specify here. The VFiler block inherits all connection related settings from the surrounding Host block (which appear before the VFiler block) but they may be overwritten inside the VFiler block.

This feature is useful, for example, when using a VFiler as SnapVault target (supported since OnTap 8.1). In that case, the SnapVault statistics are not available in the host filer (vfiler0) but only in the respective VFiler context.

Protocol httpd|http

The protocol collectd will use to query this host. Optional

Type: string

Default: https

Valid options: http, https

Address Address

The hostname or IP address of the host. Optional

Type: string

Default: The "host" block's name.

Port Port

The TCP port to connect to on the host. Optional

Type: integer

Default: 80 for protocol "http", 443 for protocol "https"

User User

Password Password

The username and password to use to login to the NetApp. Mandatory

Type: string

VFilerName Name

The name of the VFiler in which context to execute API commands. If not specified, the name provided to the VFiler block will be used instead. Optional

Type: string

Default: name of the VFiler block

Note: This option may only be used inside VFiler blocks.

Interval Interval

TODO

The following options decide what kind of data will be collected. You can either use them as a block and fine tune various parameters inside this block, use them as a single statement to just accept all default values, or omit it to not collect any data.

The following options are valid inside all blocks:

Interval Seconds

Collect the respective statistics every Seconds seconds. Defaults to the host specific setting.

The System block

This will collect various performance data about the whole system.

Note: To get this data the collectd user needs the "api-perf-object-get-instances" capability.

Interval Seconds

Collect disk statistics every Seconds seconds.

GetCPULoad true|false

If you set this option to true the current CPU usage will be read. This will be the average usage between all CPUs in your NetApp without any information about individual CPUs. Note: These are the same values that the NetApp CLI command "sysstat" returns in the "CPU" field.

Optional

Type: boolean

Default: true

Result: Two value lists of type "cpu", and type instances "idle" and "system".

GetInterfaces true|false

If you set this option to true the current traffic of the network interfaces will be read. This will be the total traffic over all interfaces of your NetApp without any information about individual interfaces. Note: This is the same values that the NetApp CLI command "sysstat" returns in the "Net kB/s" field.

Or is it?

Optional

Type: boolean

Default: true

Result: One value list of type "if_octects".

GetDiskIO true|false

If you set this option to true the current IO throughput will be read. This will be the total IO of your NetApp without any information about individual disks, volumes or aggregates. Note: This is the same values that the NetApp CLI command "sysstat" returns in the "Disk kB/s" field.

Optional

Type: boolean

Default: true

Result: One value list of type "disk_octets".

GetDiskOps true|false

If you set this option to true the current number of HTTP, NFS, CIFS, FCP, iSCSI, etc. operations will be read. This will be the total number of operations on your NetApp without any information about individual volumes or aggregates. Note: These are the same values that the NetApp CLI command "sysstat" returns in the "NFS", "CIFS", "HTTP", "FCP" and "iSCSI" fields.

Optional

Type: boolean

Default: true

Result: A variable number of value lists of type "disk_ops_complex". Each type of operation will result in one value list with the name of the operation as type instance.

The WAFL block

This will collect various performance data about the WAFL file system. At the moment this just means cache performance.

Note: To get this data the collectd user needs the "api-perf-object-get-instances" capability.

Note: The interface to get these values is classified as "Diagnostics" by NetApp. This means that it is not guaranteed to be stable even between minor releases.

Interval Seconds

Collect disk statistics every Seconds seconds.

GetNameCache true|false

Optional Type: boolean

Default: true

Result: One value list of type "cache_ratio" and type instance "name_cache_hit".

GetDirCache true|false

Optional Type: boolean

Default: true

Result: One value list of type "cache_ratio" and type instance "find_dir_hit".

GetInodeCache true|false

Optional Type: boolean

Default: true

Result: One value list of type "cache_ratio" and type instance "inode_cache_hit".

GetBufferCache true|false

Note: This is the same value that the NetApp CLI command "sysstat" returns in the "Cache hit" field. Optional

Type: boolean

Default: true

Result: One value list of type "cache_ratio" and type instance "buf_hash_hit".

The Disks block

This will collect performance data about the individual disks in the NetApp.

Note: To get this data the collectd user needs the "api-perf-object-get-instances" capability.

Interval Seconds

Collect disk statistics every Seconds seconds.

GetBusy true|false

If you set this option to true the busy time of all disks will be calculated and the value of the busiest disk in the system will be written. Note: This is the same values that the NetApp CLI command "sysstat" returns in the "Disk util" field. Probably.

Optional

Type: boolean

Default: true

Result: One value list of type "percent" and type instance "disk_busy".

The VolumePerf block

This will collect various performance data about the individual volumes.

You can select which data to collect about which volume using the following options. They follow the standard ignorelist semantic.

Note: To get this data the collectd user needs the api-perf-object-get-instances capability.

Interval Seconds

Collect volume performance data every Seconds seconds.

GetIO Volume

GetOps Volume

GetLatency Volume

Select the given volume for IO, operations or latency statistics collection. The argument is the name of the volume without the "/vol/" prefix. Since the standard ignorelist functionality is used here, you can use a string starting and ending with a slash to specify regular expression matching: To match the volumes "vol0", "vol2" and "vol7", you can use this regular expression:

```
  GetIO "/^vol[027]$/"

```

If no regular expression is specified, an exact match is required. Both, regular and exact matching are case sensitive.

If no volume was specified at all for either of the three options, that data will be collected for all available volumes.

See /"IGNORELISTS" for details.

IgnoreSelectedIO true|false

IgnoreSelectedOps true|false

IgnoreSelectedLatency true|false

When set to true, the volumes selected for IO, operations or latency statistics collection will be ignored and the data will be collected for all other volumes. When set to false, data will only be collected for the specified volumes and all other volumes will be ignored.

If no volumes have been specified with the above Get* options, all volumes will be collected regardless of the IgnoreSelected* option.

Defaults to false

The VolumeUsage block

This will collect capacity data about the individual volumes.

Note: To get this data the collectd user needs the api-volume-list-info capability.

Interval Seconds

Collect volume usage statistics every Seconds seconds.

GetCapacity VolumeName

The current capacity of the volume will be collected. This will result in two to four value lists, depending on the configuration of the volume. All data sources are of type "df_complex" with the name of the volume as plugin_instance. There will be type_instances "used" and "free" for the number of used and available bytes on the volume. If the volume has some space reserved for snapshots, a type_instance "snap_reserved" will be available. If the volume has SIS enabled, a type_instance "sis_saved" will be available. This is the number of bytes saved by the SIS feature.

Note: The current NetApp API has a bug that results in this value being reported as a 32 bit number. This plugin tries to guess the correct number which works most of the time. If you see strange values here, bug NetApp support to fix this.

Repeat this option to specify multiple volumes.

IgnoreSelectedCapacity true|false

Specify whether to collect only the volumes selected by the GetCapacity option or to ignore those volumes. IgnoreSelectedCapacity defaults to false. However, if no GetCapacity option is specified at all, all capacities will be selected anyway.

GetSnapshot VolumeName

Select volumes from which to collect snapshot information. Usually, the space used for snapshots is included in the space reported as "used". If snapshot information is collected as well, the space used for snapshots is subtracted from the used space.

To make things even more interesting, it is possible to reserve space to be used for snapshots. If the space required for snapshots is less than that reserved space, there is "reserved free" and "reserved used" space in addition to "free" and "used". If the space required for snapshots exceeds the reserved space, that part allocated in the normal space is subtracted from the "used" space again.

Repeat this option to specify multiple volumes.

IgnoreSelectedSnapshot

Specify whether to collect only the volumes selected by the GetSnapshot option or to ignore those volumes. IgnoreSelectedSnapshot defaults to false. However, if no GetSnapshot option is specified at all, all capacities will be selected anyway.

The Quota block

This will collect (tree) quota statistics (used disk space and number of used files). This mechanism is useful to get usage information for single qtrees. In case the quotas are not used for any other purpose, an entry similar to the following in "/etc/quotas" would be sufficient:

```
  /vol/volA/some_qtree tree - - - - -
```

After adding the entry, issue "quota on -w volA" on the NetApp filer.

Interval Seconds

Collect SnapVault(R) statistics every Seconds seconds.

The SnapVault block

This will collect statistics about the time and traffic of SnapVault(R) transfers.

Interval Seconds

Collect SnapVault(R) statistics every Seconds seconds.

### Plugin "netlink"
The "netlink" plugin uses a netlink socket to query the Linux kernel about statistics of various interface and routing aspects.

Interface Interface

VerboseInterface Interface

Instruct the plugin to collect interface statistics. This is basically the same as the statistics provided by the "interface" plugin (see above) but potentially much more detailed. When configuring with Interface only the basic statistics will be collected, namely octets, packets, and errors. These statistics are collected by the "interface" plugin, too, so using both at the same time is no benefit.

When configured with VerboseInterface all counters except the basic ones will be collected, so that no data needs to be collected twice if you use the "interface" plugin. This includes dropped packets, received multicast packets, collisions and a whole zoo of differentiated RX and TX errors. You can try the following command to get an idea of what awaits you:

```
  ip -s -s link list

```

If Interface is All, all interfaces will be selected.

It is possible to use regular expressions to match interface names, if the name is surrounded by /.../ and collectd was compiled with support for regexps. This is useful if there's a need to collect (or ignore) data for a group of interfaces that are similarly named, without the need to explicitly list all of them (especially useful if the list is dynamic). Examples:

```
 Interface "/^eth/"
 Interface "/^ens[1-4]$|^enp[0-3]$/"
 VerboseInterface "/^eno[0-9]+/"

```

This will match all interfaces with names starting with eth, all interfaces in range ens1 - ens4 and enp0 - enp3, and for verbose metrics all interfaces with names starting with eno followed by at least one digit.

QDisc Interface [QDisc]

Class Interface [Class]

Filter Interface [Filter]

Collect the octets and packets that pass a certain qdisc, class or filter. QDiscs and classes are identified by their type and handle (or classid). Filters don't necessarily have a handle, therefore the parent's handle is used. The notation used in collectd differs from that used in tc(1) in that it doesn't skip the major or minor number if it's zero and doesn't print special ids by their name. So, for example, a qdisc may be identified by "pfifo_fast-1:0" even though the minor number of all qdiscs is zero and thus not displayed by tc(1).

If QDisc, Class, or Filter is given without the second argument, i. .e. without an identifier, all qdiscs, classes, or filters that are associated with that interface will be collected.

Since a filter itself doesn't necessarily have a handle, the parent's handle is used. This may lead to problems when more than one filter is attached to a qdisc or class. This isn't nice, but we don't know how this could be done any better. If you have a idea, please don't hesitate to tell us.

As with the Interface option you can specify All as the interface, meaning all interfaces.

Here are some examples to help you understand the above text more easily:

```
  <Plugin netlink>
    VerboseInterface "All"
    QDisc "eth0" "pfifo_fast-1:0"
    QDisc "ppp0"
    Class "ppp0" "htb-1:10"
    Filter "ppp0" "u32-1:0"
  </Plugin>

```

See /"IGNORELISTS" for details.

IgnoreSelected

The behavior is the same as with all other similar plugins: If nothing is selected at all, everything is collected. If some things are selected using the options described above, only these statistics are collected. If you set IgnoreSelected to true, this behavior is inverted, i. e. the specified statistics will not be collected.

CollectVFStats true|false

Allow plugin to collect VF's statistics if there are Virtual Functions available for interfaces specified in Interface or VerboseInterface. All available stats are collected no matter if parent interface is set by Interface or VerboseInterface.

### Plugin "network"
The Network plugin sends data to a remote instance of collectd, receives data from a remote instance, or both at the same time. Data which has been received from the network is usually not transmitted again, but this can be activated, see the Forward option below.

The default IPv6 multicast group is "ff18::efc0:4a42". The default IPv4 multicast group is 239.192.74.66. The default UDP port is 25826.

Both, Server and Listen can be used as single option or as block. When used as block, given options are valid for this socket only. The following example will export the metrics twice: Once to an "internal" server (without encryption and signing) and one to an external server (with cryptographic signature):

```
 <Plugin "network">
   # Export to an internal server
   # (demonstrates usage without additional options)
   Server "collectd.internal.tld"
   # Export to an external server
   # (demonstrates usage with signature options)
   <Server "collectd.external.tld">
     SecurityLevel "sign"
     Username "myhostname"
     Password "ohl0eQue"
   </Server>
 </Plugin>
```

<Server Host [Port]>

The Server statement/block sets the server to send datagrams to. The statement may occur multiple times to send each datagram to multiple destinations. The argument Host may be a hostname, an IPv4 address or an IPv6 address. The optional second argument specifies a port number or a service name. If not given, the default, 25826, is used.

The following options are recognized within Server blocks:

SecurityLevel Encrypt|Sign|None

Set the security you require for network communication. When the security level has been set to Encrypt, data sent over the network will be encrypted using AES-256. The integrity of encrypted packets is ensured using SHA-1. When set to Sign, transmitted data is signed using the HMAC-SHA-256 message authentication code. When set to None, data is sent without any security. This feature is only available if the network plugin was linked with libgcrypt.

Username Username

Sets the username to transmit. This is used by the server to lookup the password. See AuthFile below. All security levels except None require this setting. This feature is only available if the network plugin was linked with libgcrypt.

Password Password

Sets a password (shared secret) for this socket. All security levels except None require this setting. This feature is only available if the network plugin was linked with libgcrypt.

Interface Interface name

Set the outgoing interface for IP packets. This applies at least to IPv6 packets and if possible to IPv4. If this option is not applicable, undefined or a non-existent interface name is specified, the default behavior is to let the kernel choose the appropriate interface. Be warned that the manual selection of an interface for unicast traffic is only necessary in rare cases.

BindAddress IP Address

Set the outgoing IP address for IP packets. This option can be used instead of the Interface option to explicitly define the IP address which will be used to send Packets to the remote server.

ResolveInterval Seconds

Sets the interval at which to re-resolve the DNS for the Host. This is useful to force a regular DNS lookup to support a high availability setup. If not specified, re-resolves are never attempted.

<Listen Host [Port]>

The Listen statement sets the interfaces to bind to. When multiple statements are found the daemon will bind to multiple interfaces. The argument Host may be a hostname, an IPv4 address or an IPv6 address. If the argument is a multicast address the daemon will join that multicast group. The optional second argument specifies a port number or a service name. If not given, the default, 25826, is used.

The following options are recognized within "<Listen>" blocks:

SecurityLevel Encrypt|Sign|None

Set the security you require for network communication. When the security level has been set to Encrypt, only encrypted data will be accepted. The integrity of encrypted packets is ensured using SHA-1. When set to Sign, only signed and encrypted data is accepted. When set to None, all data will be accepted. If an AuthFile option was given (see below), encrypted data is decrypted if possible. This feature is only available if the network plugin was linked with libgcrypt.

AuthFile Filename

Sets a file in which usernames are mapped to passwords. These passwords are used to verify signatures and to decrypt encrypted network packets. If SecurityLevel is set to None, this is optional. If given, signed data is verified and encrypted packets are decrypted. Otherwise, signed data is accepted without checking the signature and encrypted data cannot be decrypted. For the other security levels this option is mandatory. The file format is very simple: Each line consists of a username followed by a colon and any number of spaces followed by the password. To demonstrate, an example file could look like this:

```
  user0: foo
  user1: bar

```

Each time a packet is received, the modification time of the file is checked using stat(2). If the file has been changed, the contents is re-read. While the file is being read, it is locked using fcntl(2).

Interface Interface name

Set the incoming interface for IP packets explicitly. This applies at least to IPv6 packets and if possible to IPv4. If this option is not applicable, undefined or a non-existent interface name is specified, the default behavior is, to let the kernel choose the appropriate interface. Thus incoming traffic gets only accepted, if it arrives on the given interface.

TimeToLive 1-255

Set the time-to-live of sent packets. This applies to all, unicast and multicast, and IPv4 and IPv6 packets. The default is to not change this value. That means that multicast packets will be sent with a TTL of 1 (one) on most operating systems.

MaxPacketSize 1024-65535

Set the maximum size for datagrams received over the network. Packets larger than this will be truncated. Defaults to 1452 bytes, which is the maximum payload size that can be transmitted in one Ethernet frame using IPv6 / UDP. On the server side, this limit should be set to the largest value used on any client. Likewise, the value on the client must not be larger than the value on the server, or data will be lost.

Compatibility: Versions prior to version 4.8 used a fixed sized buffer of 1024 bytes. Versions 4.8, 4.9 and 4.10 used a default value of 1024 bytes to avoid problems when sending data to an older server.

Forward true|false

If set to true, write packets that were received via the network plugin to the sending sockets. This should only be activated when the Listen- and Server-statements differ. Otherwise packets may be send multiple times to the same multicast group. While this results in more network traffic than necessary it's not a huge problem since the plugin has a duplicate detection, so the values will not loop.

ReportStats true|false

The network plugin cannot only receive and send statistics, it can also create statistics about itself. Collectd data included the number of received and sent octets and packets, the length of the receive queue and the number of values handled. When set to true, the Network plugin will make these statistics available. Defaults to false.

### Plugin "nfs"
The nfs plugin collects information about the usage of the Network File System (NFS). It counts the number of procedure calls for each procedure, grouped by version and whether the system runs as server or client.

It is possibly to omit metrics for a specific NFS version by setting one or more of the following options to false (all of them default to true).

ReportV2 true|false

ReportV3 true|false

ReportV4 true|false

### Plugin "nginx"
This plugin collects the number of connections and requests handled by the "nginx daemon" (speak: engine X), a HTTP and mail server/proxy. It queries the page provided by the "ngx_http_stub_status_module" module, which isn't compiled by default. Please refer to <http://wiki.codemongers.com/NginxStubStatusModule> for more information on how to compile and configure nginx and this module.

The following options are accepted by the "nginx plugin":

URL http://host/nginx_status

Sets the URL of the "ngx_http_stub_status_module" output.

User Username

Optional user name needed for authentication.

Password Password

Optional password needed for authentication.

VerifyPeer true|false

Enable or disable peer SSL certificate verification. See <http://curl.haxx.se/docs/sslcerts.html> for details. Enabled by default.

VerifyHost true|false

Enable or disable peer host name verification. If enabled, the plugin checks if the "Common Name" or a "Subject Alternate Name" field of the SSL certificate matches the host name provided by the URL option. If this identity check fails, the connection is aborted. Obviously, only works when connecting to a SSL enabled server. Enabled by default.

CACert File

File that holds one or more SSL certificates. If you want to use HTTPS you will possibly need this option. What CA certificates come bundled with "libcurl" and are checked by default depends on the distribution you use.

Timeout Milliseconds

The Timeout option sets the overall timeout for HTTP requests to URL, in milliseconds. By default, the configured Interval is used to set the timeout.

### Plugin "notify_desktop"
This plugin sends a desktop notification to a notification daemon, as defined in the Desktop Notification Specification. To actually display the notifications, notification-daemon is required and collectd has to be able to access the X server (i. e., the "DISPLAY" and "XAUTHORITY" environment variables have to be set correctly) and the D-Bus message bus.

The Desktop Notification Specification can be found at <http://www.galago-project.org/specs/notification/>.

OkayTimeout timeout

WarningTimeout timeout

FailureTimeout timeout

Set the timeout, in milliseconds, after which to expire the notification for "OKAY", "WARNING" and "FAILURE" severities respectively. If zero has been specified, the displayed notification will not be closed at all - the user has to do so herself. These options default to 5000. If a negative number has been specified, the default is used as well.

### Plugin "notify_email"
The notify_email plugin uses the ESMTP library to send notifications to a configured email address.

libESMTP is available from <http://www.stafford.uklinux.net/libesmtp/>.

Available configuration options:

From Address

Email address from which the emails should appear to come from. Default: "root@localhost"

Recipient Address

Configures the email address(es) to which the notifications should be mailed. May be repeated to send notifications to multiple addresses. At least one Recipient must be present for the plugin to work correctly.

SMTPServer Hostname

Hostname of the SMTP server to connect to. Default: "localhost"

SMTPPort Port

TCP port to connect to. Default: 25

SMTPUser Username

Username for ASMTP authentication. Optional.

SMTPPassword Password

Password for ASMTP authentication. Optional.

Subject Subject

Subject-template to use when sending emails. There must be exactly two string-placeholders in the subject, given in the standard printf(3) syntax, i. e. %s. The first will be replaced with the severity, the second with the hostname. Default: "Collectd notify: %s@%s"

### Plugin "notify_nagios"
The notify_nagios plugin writes notifications to Nagios' command file as a passive service check result.

Available configuration options:

CommandFile Path

Sets the command file to write to. Defaults to /usr/local/nagios/var/rw/nagios.cmd.

### Plugin "ntpd"
The "ntpd" plugin collects per-peer ntp data such as time offset and time dispersion.

For talking to ntpd, it mimics what the ntpdc control program does on the wire - using mode 7 specific requests. This mode is deprecated with newer ntpd releases (4.2.7p230 and later). For the "ntpd" plugin to work correctly with them, the ntp daemon must be explicitly configured to enable mode 7 (which is disabled by default). Refer to the ntp.conf(5) manual page for details.

Available configuration options for the "ntpd" plugin:

Host Hostname

Hostname of the host running ntpd. Defaults to localhost.

Port Port

UDP-Port to connect to. Defaults to 123.

ReverseLookups true|false

Sets whether or not to perform reverse lookups on peers. Since the name or IP-address may be used in a filename it is recommended to disable reverse lookups. The default is to do reverse lookups to preserve backwards compatibility, though.

IncludeUnitID true|false

When a peer is a refclock, include the unit ID in the type instance. Defaults to false for backward compatibility. If two refclock peers use the same driver and this is false, the plugin will try to write simultaneous measurements from both to the same type instance. This will result in error messages in the log and only one set of measurements making it through.

### Plugin "nut"
UPS upsname@hostname[:port]

Add a UPS to collect data from. The format is identical to the one accepted by upsc(8).

ForceSSL true|false

Stops connections from falling back to unsecured if an SSL connection cannot be established. Defaults to false if undeclared.

VerifyPeer true|false

If set to true, requires a CAPath be provided. Will use the CAPath to find certificates to use as Trusted Certificates to validate a upsd server certificate. If validation of the upsd server certificate fails, the connection will not be established. If ForceSSL is undeclared or set to false, setting VerifyPeer to true will override and set ForceSSL to true.

CAPath I/path/to/certs/folder

If VerifyPeer is set to true, this is required. Otherwise this is ignored. The folder pointed at must contain certificate(s) named according to their hash. Ex: XXXXXXXX.Y where X is the hash value of a cert and Y is 0. If name collisions occur because two different certs have the same hash value, Y can be incremented in order to avoid conflict. To create a symbolic link to a certificate the following command can be used from within the directory where the cert resides: "ln -s some.crt ./$(openssl x509 -hash -noout -in some.crt).0"

Alternatively, the package openssl-perl provides a command "c_rehash" that will generate links like the one described above for ALL certs in a given folder. Example usage: "c_rehash /path/to/certs/folder"

ConnectTimeout Milliseconds

The ConnectTimeout option sets the connect timeout, in milliseconds. By default, the configured Interval is used to set the timeout.

### Plugin "olsrd"
The olsrd plugin connects to the TCP port opened by the txtinfo plugin of the Optimized Link State Routing daemon and reads information about the current state of the meshed network.

The following configuration options are understood:

Host Host

Connect to Host. Defaults to "localhost".

Port Port

Specifies the port to connect to. This must be a string, even if you give the port as a number rather than a service name. Defaults to "2006".

CollectLinks No|Summary|Detail

Specifies what information to collect about links, i. e. direct connections of the daemon queried. If set to No, no information is collected. If set to Summary, the number of links and the average of all link quality (LQ) and neighbor link quality (NLQ) values is calculated. If set to Detail LQ and NLQ are collected per link. Defaults to Detail.

CollectRoutes No|Summary|Detail

Specifies what information to collect about routes of the daemon queried. If set to No, no information is collected. If set to Summary, the number of routes and the average metric and ETX is calculated. If set to Detail metric and ETX are collected per route. Defaults to Summary.

CollectTopology No|Summary|Detail

Specifies what information to collect about the global topology. If set to No, no information is collected. If set to Summary, the number of links in the entire topology and the average link quality (LQ) is calculated. If set to Detail LQ and NLQ are collected for each link in the entire topology. Defaults to Summary.

### Plugin "onewire"
EXPERIMENTAL! See notes below.

The "onewire" plugin uses the owcapi library from the owfs project <http://owfs.org/> to read sensors connected via the onewire bus.

It can be used in two possible modes - standard or advanced.

In the standard mode only temperature sensors (sensors with the family code 10, 22 and 28 - e.g. DS1820, DS18S20, DS1920) can be read. If you have other sensors you would like to have included, please send a sort request to the mailing list. You can select sensors to be read or to be ignored depending on the option IgnoreSelected). When no list is provided the whole bus is walked and all sensors are read.

Hubs (the DS2409 chips) are working, but read the note, why this plugin is experimental, below.

In the advanced mode you can configure any sensor to be read (only numerical value) using full OWFS path (e.g. "/uncached/10.F10FCA000800/temperature"). In this mode you have to list all the sensors. Neither default bus walk nor IgnoreSelected are used here. Address and type (file) is extracted from the path automatically and should produce compatible structure with the "standard" mode (basically the path is expected as for example "/uncached/10.F10FCA000800/temperature" where it would extract address part "F10FCA000800" and the rest after the slash is considered the type - here "temperature"). There are two advantages to this mode - you can access virtually any sensor (not just temperature), select whether to use cached or directly read values and it is slighlty faster. The downside is more complex configuration.

The two modes are distinguished automatically by the format of the address. It is not possible to mix the two modes. Once a full path is detected in any Sensor then the whole addressing (all sensors) is considered to be this way (and as standard addresses will fail parsing they will be ignored).

Device Device

Sets the device to read the values from. This can either be a "real" hardware device, such as a serial port or an USB port, or the address of the owserver(1) socket, usually localhost:4304. Though the documentation claims to automatically recognize the given address format, with version 2.7p4 we had to specify the type explicitly. So with that version, the following configuration worked for us:

```
  <Plugin onewire>
    Device "-s localhost:4304"
  </Plugin>

```

This directive is required and does not have a default value.

Sensor Sensor

In the standard mode selects sensors to collect or to ignore (depending on IgnoreSelected, see below). Sensors are specified without the family byte at the beginning, so you have to use for example "F10FCA000800", and not include the leading 10. family byte and point. When no Sensor is configured the whole Onewire bus is walked and all supported sensors (see above) are read. In the advanced mode the Sensor specifies full OWFS path - e.g. "/uncached/10.F10FCA000800/temperature" (or when cached values are OK "/10.F10FCA000800/temperature"). IgnoreSelected is not used.

As there can be multiple devices on the bus you can list multiple sensor (use multiple Sensor elements).

See /"IGNORELISTS" for details.

IgnoreSelected true|false

If no configuration is given, the onewire plugin will collect data from all sensors found. This may not be practical, especially if sensors are added and removed regularly. Sometimes, however, it's easier/preferred to collect only specific sensors or all sensors except a few specified ones. This option enables you to do that: By setting IgnoreSelected to true the effect of Sensor is inverted: All selected interfaces are ignored and all other interfaces are collected. Used only in the standard mode - see above.

Interval Seconds

Sets the interval in which all sensors should be read. If not specified, the global Interval setting is used.

EXPERIMENTAL! The "onewire" plugin is experimental, because it doesn't yet work with big setups. It works with one sensor being attached to one controller, but as soon as you throw in a couple more senors and maybe a hub or two, reading all values will take more than ten seconds (the default interval). We will probably add some separate thread for reading the sensors and some cache or something like that, but it's not done yet. We will try to maintain backwards compatibility in the future, but we can't promise. So in short: If it works for you: Great! But keep in mind that the config might change, though this is unlikely. Oh, and if you want to help improving this plugin, just send a short notice to the mailing list. Thanks :)

### Plugin "openldap"
To use the "openldap" plugin you first need to configure the OpenLDAP server correctly. The backend database "monitor" needs to be loaded and working. See slapd-monitor(5) for the details.

The configuration of the "openldap" plugin consists of one or more Instance blocks. Each block requires one string argument as the instance name. For example:

```
 <Plugin "openldap">
   <Instance "foo">
     URL "ldap://localhost/"
   </Instance>
   <Instance "bar">
     URL "ldaps://localhost/"
   </Instance>
 </Plugin>
```

The instance name will be used as the plugin instance. To emulate the old (version 4) behavior, you can use an empty string (""). In order for the plugin to work correctly, each instance name must be unique. This is not enforced by the plugin and it is your responsibility to ensure it is.

The following options are accepted within each Instance block:

URL ldap://host/binddn

Sets the URL to use to connect to the OpenLDAP server. This option is mandatory.

BindDN BindDN

Name in the form of an LDAP distinguished name intended to be used for authentication. Defaults to empty string to establish an anonymous authorization.

Password Password

Password for simple bind authentication. If this option is not set, unauthenticated bind operation is used.

StartTLS true|false

Defines whether TLS must be used when connecting to the OpenLDAP server. Disabled by default.

VerifyHost true|false

Enables or disables peer host name verification. If enabled, the plugin checks if the "Common Name" or a "Subject Alternate Name" field of the SSL certificate matches the host name provided by the URL option. If this identity check fails, the connection is aborted. Enabled by default.

CACert File

File that holds one or more SSL certificates. If you want to use TLS/SSL you may possibly need this option. What CA certificates are checked by default depends on the distribution you use and can be changed with the usual ldap client configuration mechanisms. See ldap.conf(5) for the details.

Timeout Seconds

Sets the timeout value for ldap operations, in seconds. By default, the configured Interval is used to set the timeout. Use -1 to disable (infinite timeout).

Version Version

An integer which sets the LDAP protocol version number to use when connecting to the OpenLDAP server. Defaults to 3 for using LDAPv3.

### Plugin "openvpn"
The OpenVPN plugin reads a status file maintained by OpenVPN and gathers traffic statistics about connected clients.

To set up OpenVPN to write to the status file periodically, use the --status option of OpenVPN.

So, in a nutshell you need:

```
  openvpn $OTHER_OPTIONS \
    --status "/var/run/openvpn-status" 10
```

Available options:

StatusFile File

Specifies the location of the status file.

ImprovedNamingSchema true|false

When enabled, the filename of the status file will be used as plugin instance and the client's "common name" will be used as type instance. This is required when reading multiple status files. Enabling this option is recommended, but to maintain backwards compatibility this option is disabled by default.

CollectCompression true|false

Sets whether or not statistics about the compression used by OpenVPN should be collected. This information is only available in single mode. Enabled by default.

CollectIndividualUsers true|false

Sets whether or not traffic information is collected for each connected client individually. If set to false, currently no traffic data is collected at all because aggregating this data in a save manner is tricky. Defaults to true.

CollectUserCount true|false

When enabled, the number of currently connected clients or users is collected. This is especially interesting when CollectIndividualUsers is disabled, but can be configured independently from that option. Defaults to false.

### Plugin "oracle"
The "oracle" plugin uses the OracleX Call Interface (OCI) to connect to an OracleX Database and lets you execute SQL statements there. It is very similar to the "dbi" plugin, because it was written around the same time. See the "dbi" plugin's documentation above for details.

```
  <Plugin oracle>
    <Query "out_of_stock">
      Statement "SELECT category, COUNT(*) AS value FROM products WHERE in_stock = 0 GROUP BY category"
      <Result>
        Type "gauge"
        # InstancePrefix "foo"
        InstancesFrom "category"
        ValuesFrom "value"
      </Result>
    </Query>
    <Database "product_information">
      #Plugin "warehouse"
      ConnectID "db01"
      Username "oracle"
      Password "secret"
      Query "out_of_stock"
    </Database>
  </Plugin>
```

Query blocks

The Query blocks are handled identically to the Query blocks of the "dbi" plugin. Please see its documentation above for details on how to specify queries.

Database blocks

Database blocks define a connection to a database and which queries should be sent to that database. Each database needs a "name" as string argument in the starting tag of the block. This name will be used as "PluginInstance" in the values submitted to the daemon. Other than that, that name is not used.

Plugin Plugin

Use Plugin as the plugin name when submitting query results from this Database. Defaults to "oracle".

ConnectID ID

Defines the "database alias" or "service name" to connect to. Usually, these names are defined in the file named "$ORACLE_HOME/network/admin/tnsnames.ora".

Host Host

Hostname to use when dispatching values for this database. Defaults to using the global hostname of the collectd instance.

Username Username

Username used for authentication.

Password Password

Password used for authentication.

Query QueryName

Associates the query named QueryName with this database connection. The query needs to be defined before this statement, i. e. all query blocks you want to refer to must be placed above the database block you want to refer to them from.

### Plugin "ovs_events"
The ovs_events plugin monitors the link status of Open vSwitch (OVS) connected interfaces, dispatches the values to collectd and sends the notification whenever the link state change occurs. This plugin uses OVS database to get a link state change notification.

Synopsis:

```
 <Plugin "ovs_events">
   Port 6640
   Address "127.0.0.1"
   Socket "/var/run/openvswitch/db.sock"
   Interfaces "br0" "veth0"
   SendNotification true
   DispatchValues false
 </Plugin>
```

The plugin provides the following configuration options:

Address node

The address of the OVS DB server JSON-RPC interface used by the plugin. To enable the interface, OVS DB daemon should be running with "--remote=ptcp:" option. See ovsdb-server(1) for more details. The option may be either network hostname, IPv4 numbers-and-dots notation or IPv6 hexadecimal string format. Defaults to "localhost".

Port service

TCP-port to connect to. Either a service name or a port number may be given. Defaults to 6640.

Socket path

The UNIX domain socket path of OVS DB server JSON-RPC interface used by the plugin. To enable the interface, the OVS DB daemon should be running with "--remote=punix:" option. See ovsdb-server(1) for more details. If this option is set, Address and Port options are ignored.

Interfaces [ifname ...]

List of interface names to be monitored by this plugin. If this option is not specified or is empty then all OVS connected interfaces on all bridges are monitored. Default: empty (all interfaces on all bridges are monitored)

SendNotification true|false

If set to true, OVS link notifications (interface status and OVS DB connection terminate) are sent to collectd. Default value is true.

DispatchValues true|false

Dispatch the OVS DB interface link status value with configured plugin interval. Defaults to false. Please note, if SendNotification and DispatchValues options are false, no OVS information will be provided by the plugin.

Note: By default, the global interval setting is used within which to retrieve the OVS link status. To configure a plugin-specific interval, please use Interval option of the OVS LoadPlugin block settings. For milliseconds simple divide the time by 1000 for example if the desired interval is 50ms, set interval to 0.05.

### Plugin "ovs_stats"
The ovs_stats plugin collects statistics of OVS connected interfaces. This plugin uses OVSDB management protocol (RFC7047) monitor mechanism to get statistics from OVSDB

Synopsis:

```
 <Plugin "ovs_stats">
   Port 6640
   Address "127.0.0.1"
   Socket "/var/run/openvswitch/db.sock"
   Bridges "br0" "br_ext"
   InterfaceStats false
 </Plugin>
```

The plugin provides the following configuration options:

Address node

The address of the OVS DB server JSON-RPC interface used by the plugin. To enable the interface, OVS DB daemon should be running with "--remote=ptcp:" option. See ovsdb-server(1) for more details. The option may be either network hostname, IPv4 numbers-and-dots notation or IPv6 hexadecimal string format. Defaults to "localhost".

Port service

TCP-port to connect to. Either a service name or a port number may be given. Defaults to 6640.

Socket path

The UNIX domain socket path of OVS DB server JSON-RPC interface used by the plugin. To enable the interface, the OVS DB daemon should be running with "--remote=punix:" option. See ovsdb-server(1) for more details. If this option is set, Address and Port options are ignored.

Bridges [brname ...]

List of OVS bridge names to be monitored by this plugin. If this option is omitted or is empty then all OVS bridges will be monitored. Default: empty (monitor all bridges)

InterfaceStats false|true

Indicates that the plugin should gather statistics for individual interfaces in addition to ports. This can be useful when monitoring an OVS setup with bond ports, where you might wish to know individual statistics for the interfaces included in the bonds. Defaults to false.

### Plugin "pcie_errors"
The pcie_errors plugin collects PCI Express errors from Device Status in Capability structure and from Advanced Error Reporting Extended Capability where available. At every read it polls config space of PCI Express devices and dispatches notification for every error that is set. It checks for new errors at every read. The device is indicated in plugin_instance according to format "domain:bus:dev.fn". Errors are divided into categories indicated by type_instance: "correctable", and for uncorrectable errors "non_fatal" or "fatal". Fatal errors are reported as NOTIF_FAILURE and all others as NOTIF_WARNING.

Synopsis:

```
  <Plugin "pcie_errors">
    Source "sysfs"
    AccessDir "/sys/bus/pci"
    ReportMasked false
    PersistentNotifications false
  </Plugin>
```

Options:

Source sysfs|proc

Use sysfs or proc to read data from /sysfs or /proc. The default value is sysfs.

AccessDir dir

Directory used to access device config space. It is optional and defaults to /sys/bus/pci for sysfs and to /proc/bus/pci for proc.

ReportMasked false|true

If true plugin will notify about errors that are set to masked in Error Mask register. Such errors are not reported to the PCI Express Root Complex. Defaults to false.

PersistentNotifications false|true

If false plugin will dispatch notification only on set/clear of error. The ones already reported will be ignored. Defaults to false.

### Plugin "perl"
This plugin embeds a Perl-interpreter into collectd and provides an interface to collectd's plugin system. See collectd-perl(5) for its documentation.

### Plugin "pinba"
The Pinba plugin receives profiling information from Pinba, an extension for the PHP interpreter. At the end of executing a script, i.e. after a PHP-based webpage has been delivered, the extension will send a UDP packet containing timing information, peak memory usage and so on. The plugin will wait for such packets, parse them and account the provided information, which is then dispatched to the daemon once per interval.

Synopsis:

```
 <Plugin pinba>
   Address "::0"
   Port "30002"
   # Overall statistics for the website.
   <View "www-total">
     Server "www.example.com"
   </View>
   # Statistics for www-a only
   <View "www-a">
     Host "www-a.example.com"
     Server "www.example.com"
   </View>
   # Statistics for www-b only
   <View "www-b">
     Host "www-b.example.com"
     Server "www.example.com"
   </View>
 </Plugin>
```

The plugin provides the following configuration options:

Address Node

Configures the address used to open a listening socket. By default, plugin will bind to the any address "::0".

Port Service

Configures the port (service) to bind to. By default the default Pinba port "30002" will be used. The option accepts service names in addition to port numbers and thus requires a string argument.

<View Name> block

The packets sent by the Pinba extension include the hostname of the server, the server name (the name of the virtual host) and the script that was executed. Using View blocks it is possible to separate the data into multiple groups to get more meaningful statistics. Each packet is added to all matching groups, so that a packet may be accounted for more than once.

Host Host

Matches the hostname of the system the webserver / script is running on. This will contain the result of the gethostname(2) system call. If not configured, all hostnames will be accepted.

Server Server

Matches the name of the virtual host, i.e. the contents of the $_SERVER["SERVER_NAME"] variable when within PHP. If not configured, all server names will be accepted.

Script Script

Matches the name of the script name, i.e. the contents of the $_SERVER["SCRIPT_NAME"] variable when within PHP. If not configured, all script names will be accepted.

### Plugin "ping"
The Ping plugin starts a new thread which sends ICMP "ping" packets to the configured hosts periodically and measures the network latency. Whenever the "read" function of the plugin is called, it submits the average latency, the standard deviation and the drop rate for each host.

Available configuration options:

Host IP-address

Host to ping periodically. This option may be repeated several times to ping multiple hosts.

Interval Seconds

Sets the interval in which to send ICMP echo packets to the configured hosts. This is not the interval in which metrics are read from the plugin but the interval in which the hosts are "pinged". Therefore, the setting here should be smaller than or equal to the global Interval setting. Fractional times, such as "1.24" are allowed. Default: 1.0

Timeout Seconds

Time to wait for a response from the host to which an ICMP packet had been sent. If a reply was not received after Seconds seconds, the host is assumed to be down or the packet to be dropped. This setting must be smaller than the Interval setting above for the plugin to work correctly. Fractional arguments are accepted. Default: 0.9

TTL 0-255

Sets the Time-To-Live of generated ICMP packets.

Size size

Sets the size of the data payload in ICMP packet to specified size (it will be filled with regular ASCII pattern). If not set, default 56 byte long string is used so that the packet size of an ICMPv4 packet is exactly 64 bytes, similar to the behaviour of normal ping(1) command.

SourceAddress host

Sets the source address to use. host may either be a numerical network address or a network hostname.

AddressFamily af

Sets the address family to use. af may be "any", "ipv4" or "ipv6". This option will be ignored if you set a SourceAddress.

Device name

Sets the outgoing network device to be used. name has to specify an interface name (e. g. "eth0"). This might not be supported by all operating systems.

MaxMissed Packets

Trigger a DNS resolve after the host has not replied to Packets packets. This enables the use of dynamic DNS services (like dyndns.org) with the ping plugin. Default: -1 (disabled)

### Plugin "postgresql"
The "postgresql" plugin queries statistics from PostgreSQL databases. It keeps a persistent connection to all configured databases and tries to reconnect if the connection has been interrupted. A database is configured by specifying a Database block as described below. The default statistics are collected from PostgreSQL's statistics collector which thus has to be enabled for this plugin to work correctly. This should usually be the case by default. See the section "The Statistics Collector" of the PostgreSQL Documentation for details.

By specifying custom database queries using a Query block as described below, you may collect any data that is available from some PostgreSQL database. This way, you are able to access statistics of external daemons which are available in a PostgreSQL database or use future or special statistics provided by PostgreSQL without the need to upgrade your collectd installation.

Starting with version 5.2, the "postgresql" plugin supports writing data to PostgreSQL databases as well. This has been implemented in a generic way. You need to specify an SQL statement which will then be executed by collectd in order to write the data (see below for details). The benefit of that approach is that there is no fixed database layout. Rather, the layout may be optimized for the current setup.

The PostgreSQL Documentation manual can be found at <http://www.postgresql.org/docs/manuals/>.

```
  <Plugin postgresql>
    <Query magic>
      Statement "SELECT magic FROM wizard WHERE host = $1;"
      Param hostname
      <Result>
        Type gauge
        InstancePrefix "magic"
        ValuesFrom magic
      </Result>
    </Query>
    <Query rt36_tickets>
      Statement "SELECT COUNT(type) AS count, type \
                        FROM (SELECT CASE \
                                     WHEN resolved = 'epoch' THEN 'open' \
                                     ELSE 'resolved' END AS type \
                                     FROM tickets) type \
                        GROUP BY type;"
      <Result>
        Type counter
        InstancePrefix "rt36_tickets"
        InstancesFrom "type"
        ValuesFrom "count"
      </Result>
    </Query>
    <Writer sqlstore>
      Statement "SELECT collectd_insert($1, $2, $3, $4, $5, $6, $7, $8, $9);"
      StoreRates true
    </Writer>
    <Database foo>
      Plugin "kingdom"
      Host "hostname"
      Port "5432"
      User "username"
      Password "secret"
      SSLMode "prefer"
      KRBSrvName "kerberos_service_name"
      Query magic
    </Database>
    <Database bar>
      Interval 300
      Service "service_name"
      Query backends # predefined
      Query rt36_tickets
    </Database>
    <Database qux>
      # ...
      Writer sqlstore
      CommitInterval 10
    </Database>
  </Plugin>
```

The Query block defines one database query which may later be used by a database definition. It accepts a single mandatory argument which specifies the name of the query. The names of all queries have to be unique (see the MinVersion and MaxVersion options below for an exception to this rule).

In each Query block, there is one or more Result blocks. Multiple Result blocks may be used to extract multiple values from a single query.

The following configuration options are available to define the query:

Statement sql query statement

Specify the sql query statement which the plugin should execute. The string may contain the tokens $1, $2, etc. which are used to reference the first, second, etc. parameter. The value of the parameters is specified by the Param configuration option - see below for details. To include a literal $ character followed by a number, surround it with single quotes ('). Any SQL command which may return data (such as "SELECT" or "SHOW") is allowed. Note, however, that only a single command may be used. Semicolons are allowed as long as a single non-empty command has been specified only.

The returned lines will be handled separately one after another.

Param hostname|database|instance|username|interval

Specify the parameters which should be passed to the SQL query. The parameters are referred to in the SQL query as $1, $2, etc. in the same order as they appear in the configuration file. The value of the parameter is determined depending on the value of the Param option as follows:

hostname

The configured hostname of the database connection. If a UNIX domain socket is used, the parameter expands to "localhost".

database

The name of the database of the current connection.

instance

The name of the database plugin instance. See the Instance option of the database specification below for details.

username

The username used to connect to the database.

interval

The interval with which this database is queried (as specified by the database specific or global Interval options).

Please note that parameters are only supported by PostgreSQL's protocol version 3 and above which was introduced in version 7.4 of PostgreSQL.

PluginInstanceFrom column

Specify how to create the "PluginInstance" for reporting this query results. Only one column is supported. You may concatenate fields and string values in the query statement to get the required results.

MinVersion version

MaxVersion version

Specify the minimum or maximum version of PostgreSQL that this query should be used with. Some statistics might only be available with certain versions of PostgreSQL. This allows you to specify multiple queries with the same name but which apply to different versions, thus allowing you to use the same configuration in a heterogeneous environment. The version has to be specified as the concatenation of the major, minor and patch-level versions, each represented as two-decimal-digit numbers. For example, version 8.2.3 will become 80203.

The Result block defines how to handle the values returned from the query. It defines which column holds which value and how to dispatch that value to the daemon.

Type type

The type name to be used when dispatching the values. The type describes how to handle the data and where to store it. See types.db(5) for more details on types and their configuration. The number and type of values (as selected by the ValuesFrom option) has to match the type of the given name. This option is mandatory.

InstancePrefix prefix

InstancesFrom column0 [column1 ...]

Specify how to create the "TypeInstance" for each data set (i. e. line). InstancePrefix defines a static prefix that will be prepended to all type instances. InstancesFrom defines the column names whose values will be used to create the type instance. Multiple values will be joined together using the hyphen ("-") as separation character. The plugin itself does not check whether or not all built instances are different. It is your responsibility to assure that each is unique.

Both options are optional. If none is specified, the type instance will be empty.

ValuesFrom column0 [column1 ...]

Names the columns whose content is used as the actual data for the data sets that are dispatched to the daemon. How many such columns you need is determined by the Type setting as explained above. If you specify too many or not enough columns, the plugin will complain about that and no data will be submitted to the daemon. The actual data type, as seen by PostgreSQL, is not that important as long as it represents numbers. The plugin will automatically cast the values to the right type if it know how to do that. For that, it uses the strtoll(3) and strtod(3) functions, so anything supported by those functions is supported by the plugin as well.

This option is required inside a Result block and may be specified multiple times. If multiple ValuesFrom options are specified, the columns are read in the given order.

The following predefined queries are available (the definitions can be found in the postgresql_default.conf file which, by default, is available at "prefix/share/collectd/"):

backends

This query collects the number of backends, i. e. the number of connected clients.

transactions

This query collects the numbers of committed and rolled-back transactions of the user tables.

queries

This query collects the numbers of various table modifications (i. e. insertions, updates, deletions) of the user tables.

query_plans

This query collects the numbers of various table scans and returned tuples of the user tables.

table_states

This query collects the numbers of live and dead rows in the user tables.

disk_io

This query collects disk block access counts for user tables.

disk_usage

This query collects the on-disk size of the database in bytes.

In addition, the following detailed queries are available by default. Please note that each of those queries collects information by table, thus, potentially producing a lot of data. For details see the description of the non-by_table queries above.

queries_by_table

query_plans_by_table

table_states_by_table

disk_io_by_table

The Writer block defines a PostgreSQL writer backend. It accepts a single mandatory argument specifying the name of the writer. This will then be used in the Database specification in order to activate the writer instance. The names of all writers have to be unique. The following options may be specified:

Statement sql statement

This mandatory option specifies the SQL statement that will be executed for each submitted value. A single SQL statement is allowed only. Anything after the first semicolon will be ignored. Nine parameters will be passed to the statement and should be specified as tokens $1, $2, through $9 in the statement string. The following values are made available through those parameters:

$1

The timestamp of the queried value as an RFC 3339-formatted local time.

$2

The hostname of the queried value.

$3

The plugin name of the queried value.

$4

The plugin instance of the queried value. This value may be NULL if there is no plugin instance.

$5

The type of the queried value (cf. types.db(5)).

$6

The type instance of the queried value. This value may be NULL if there is no type instance.

$7

An array of names for the submitted values (i. e., the name of the data sources of the submitted value-list).

$8

An array of types for the submitted values (i. e., the type of the data sources of the submitted value-list; "counter", "gauge", ...). Note, that if StoreRates is enabled (which is the default, see below), all types will be "gauge".

$9

An array of the submitted values. The dimensions of the value name and value arrays match.

In general, it is advisable to create and call a custom function in the PostgreSQL database for this purpose. Any procedural language supported by PostgreSQL will do (see chapter "Server Programming" in the PostgreSQL manual for details).

StoreRates false|true

If set to true (the default), convert counter values to rates. If set to false counter values are stored as is, i. e. as an increasing integer number.

The Database block defines one PostgreSQL database for which to collect statistics. It accepts a single mandatory argument which specifies the database name. None of the other options are required. PostgreSQL will use default values as documented in the section "CONNECTING TO A DATABASE" in the psql(1) manpage. However, be aware that those defaults may be influenced by the user collectd is run as and special environment variables. See the manpage for details.

Interval seconds

Specify the interval with which the database should be queried. The default is to use the global Interval setting.

CommitInterval seconds

This option may be used for database connections which have "writers" assigned (see above). If specified, it causes a writer to put several updates into a single transaction. This transaction will last for the specified amount of time. By default, each update will be executed in a separate transaction. Each transaction generates a fair amount of overhead which can, thus, be reduced by activating this option. The draw-back is, that data covering the specified amount of time will be lost, for example, if a single statement within the transaction fails or if the database server crashes.

Plugin Plugin

Use Plugin as the plugin name when submitting query results from this Database. Defaults to "postgresql".

Instance name

Specify the plugin instance name that should be used instead of the database name (which is the default, if this option has not been specified). This allows one to query multiple databases of the same name on the same host (e.g. when running multiple database server versions in parallel). The plugin instance name can also be set from the query result using the PluginInstanceFrom option in Query block.

Host hostname

Specify the hostname or IP of the PostgreSQL server to connect to. If the value begins with a slash, it is interpreted as the directory name in which to look for the UNIX domain socket. This option is also used to determine the hostname that is associated with a collected data set. If it has been omitted or either begins with with a slash or equals localhost it will be replaced with the global hostname definition of collectd. Any other value will be passed literally to collectd when dispatching values. Also see the global Hostname and FQDNLookup options.

Port port

Specify the TCP port or the local UNIX domain socket file extension of the server.

User username

Specify the username to be used when connecting to the server.

Password password

Specify the password to be used when connecting to the server.

ExpireDelay delay

Skip expired values in query output.

SSLMode disable|allow|prefer|require

Specify whether to use an SSL connection when contacting the server. The following modes are supported:

disable

Do not use SSL at all.

allow

First, try to connect without using SSL. If that fails, try using SSL.

prefer (default)

First, try to connect using SSL. If that fails, try without using SSL.

require

Use SSL only.

Instance name

Specify the plugin instance name that should be used instead of the database name (which is the default, if this option has not been specified). This allows one to query multiple databases of the same name on the same host (e.g. when running multiple database server versions in parallel).

KRBSrvName kerberos_service_name

Specify the Kerberos service name to use when authenticating with Kerberos 5 or GSSAPI. See the sections "Kerberos authentication" and "GSSAPI" of the PostgreSQL Documentation for details.

Service service_name

Specify the PostgreSQL service name to use for additional parameters. That service has to be defined in pg_service.conf and holds additional connection parameters. See the section "The Connection Service File" in the PostgreSQL Documentation for details.

Query query

Specifies a query which should be executed in the context of the database connection. This may be any of the predefined or user-defined queries. If no such option is given, it defaults to "backends", "transactions", "queries", "query_plans", "table_states", "disk_io" and "disk_usage" (unless a Writer has been specified). Else, the specified queries are used only.

Writer writer

Assigns the specified writer backend to the database connection. This causes all collected data to be send to the database using the settings defined in the writer configuration (see the section "FILTER CONFIGURATION" below for details on how to selectively send data to certain plugins). Each writer will register a flush callback which may be used when having long transactions enabled (see the CommitInterval option above). When issuing the FLUSH command (see collectd-unixsock(5) for details) the current transaction will be committed right away. Two different kinds of flush callbacks are available with the "postgresql" plugin:

postgresql

Flush all writer backends.

postgresql-database

Flush all writers of the specified database only.

### Plugin "powerdns"
The "powerdns" plugin queries statistics from an authoritative PowerDNS nameserver and/or a PowerDNS recursor. Since both offer a wide variety of values, many of which are probably meaningless to most users, but may be useful for some. So you may chose which values to collect, but if you don't, some reasonable defaults will be collected.

```
  <Plugin "powerdns">
    <Server "server_name">
      Collect "latency"
      Collect "udp-answers" "udp-queries"
      Socket "/var/run/pdns.controlsocket"
    </Server>
    <Recursor "recursor_name">
      Collect "questions"
      Collect "cache-hits" "cache-misses"
      Socket "/var/run/pdns_recursor.controlsocket"
    </Recursor>
    LocalSocket "/opt/collectd/var/run/collectd-powerdns"
  </Plugin>
```

Server and Recursor block

The Server block defines one authoritative server to query, the Recursor does the same for an recursing server. The possible options in both blocks are the same, though. The argument defines a name for the server / recursor and is required.

Collect Field

Using the Collect statement you can select which values to collect. Here, you specify the name of the values as used by the PowerDNS servers, e. g. "dlg-only-drops", "answers10-100". The method of getting the values differs for Server and Recursor blocks: When querying the server a "SHOW *" command is issued in any case, because that's the only way of getting multiple values out of the server at once. collectd then picks out the values you have selected. When querying the recursor, a command is generated to query exactly these values. So if you specify invalid fields when querying the recursor, a syntax error may be returned by the daemon and collectd may not collect any values at all.

If no Collect statement is given, the following Server values will be collected:

latency

packetcache-hit

packetcache-miss

packetcache-size

query-cache-hit

query-cache-miss

recursing-answers

recursing-questions

tcp-answers

tcp-queries

udp-answers

udp-queries

The following Recursor values will be collected by default:

noerror-answers

nxdomain-answers

servfail-answers

sys-msec

user-msec

qa-latency

cache-entries

cache-hits

cache-misses

questions

Please note that up to that point collectd doesn't know what values are available on the server and values that are added do not need a change of the mechanism so far. However, the values must be mapped to collectd's naming scheme, which is done using a lookup table that lists all known values. If values are added in the future and collectd does not know about them, you will get an error much like this:

```
  powerdns plugin: submit: Not found in lookup table: foobar = 42
```

In this case please file a bug report with the collectd team.

Socket Path

Configures the path to the UNIX domain socket to be used when connecting to the daemon. By default "${localstatedir}/run/pdns.controlsocket" will be used for an authoritative server and "${localstatedir}/run/pdns_recursor.controlsocket" will be used for the recursor.

LocalSocket Path

Querying the recursor is done using UDP. When using UDP over UNIX domain sockets, the client socket needs a name in the file system, too. You can set this local name to Path using the LocalSocket option. The default is "prefix/var/run/collectd-powerdns".

### Plugin "processes"
Collects information about processes of local system.

By default, with no process matches configured, only general statistics is collected: the number of processes in each state and fork rate.

Process matches can be configured by Process and ProcessMatch options. These may also be a block in which further options may be specified.

The statistics collected for matched processes are:

- size of the resident segment size (RSS)

- user- and system-time used

- number of processes

- number of threads

- number of open files (under Linux)

- number of memory mapped files (under Linux)

- io data (where available)

- context switches (under Linux)

- minor and major pagefaults

- Delay Accounting information (Linux only, requires libmnl)

Synopsis:

```
 <Plugin processes>
   CollectFileDescriptor  true
   CollectContextSwitch   true
   CollectDelayAccounting false
   Process "name"
   ProcessMatch "name" "regex"
   <Process "collectd">
     CollectFileDescriptor  false
     CollectContextSwitch   false
     CollectDelayAccounting true
   </Process>
   <ProcessMatch "name" "regex">
     CollectFileDescriptor false
     CollectContextSwitch true
   </ProcessMatch>
 </Plugin>
```

Process Name

Select more detailed statistics of processes matching this name. Some platforms have a limit on the length of process names. Name must stay below this limit.

ProcessMatch name regex

Select more detailed statistics of processes matching the specified regex (see regex(7) for details). The statistics of all matching processes are summed up and dispatched to the daemon using the specified name as an identifier. This allows one to "group" several processes together. name must not contain slashes.

CollectContextSwitch Boolean

Collect the number of context switches for matched processes. Disabled by default.

CollectDelayAccounting Boolean

If enabled, collect Linux Delay Accounding information for matching processes. Delay Accounting provides the time processes wait for the CPU to become available, for I/O operations to finish, for pages to be swapped in and for freed pages to be reclaimed. The metrics are reported as "seconds per second" using the "delay_rate" type, e.g. "delay_rate-delay-cpu". Disabled by default. This option is only available on Linux, requires the "libmnl" library and requires the "CAP_NET_ADMIN" capability at runtime.

CollectFileDescriptor Boolean

Collect number of file descriptors of matched processes. Disabled by default.

CollectMemoryMaps Boolean

Collect the number of memory mapped files of the process. The limit for this number is configured via /proc/sys/vm/max_map_count in the Linux kernel.

The CollectContextSwitch, CollectDelayAccounting, CollectFileDescriptor and CollectMemoryMaps options may be used inside Process and ProcessMatch blocks. When used there, these options affect reporting the corresponding processes only. Outside of Process and ProcessMatch blocks these options set the default value for subsequent matches.

### Plugin "procevent"
The procevent plugin monitors when processes start (EXEC) and stop (EXIT).

Synopsis:

```
  <Plugin procevent>
    BufferLength 10
    Process "name"
    ProcessRegex "regex"
  </Plugin>
```

Options:

BufferLength length

Maximum number of process events that can be stored in plugin's ring buffer. By default, this is set to 10. Once an event has been read, its location becomes available for storing a new event.

Process name

Enumerate a process name to monitor. All processes that match this exact name will be monitored for EXECs and EXITs.

ProcessRegex regex

Enumerate a process pattern to monitor. All processes that match this regular expression will be monitored for EXECs and EXITs.

### Plugin "protocols"
Collects a lot of information about various network protocols, such as IP, TCP, UDP, etc.

Available configuration options:

Value Selector

Selects whether or not to select a specific value. The string being matched is of the form "Protocol:ValueName", where Protocol will be used as the plugin instance and ValueName will be used as type instance. An example of the string being used would be "Tcp:RetransSegs". You can use regular expressions to match a large number of values with just one configuration option. To select all "extended" TCP values, you could use the following statement:

```
  Value "/^TcpExt:/"

```

Whether only matched values are selected or all matched values are ignored depends on the IgnoreSelected. By default, only matched values are selected. If no value is configured at all, all values will be selected.

See /"IGNORELISTS" for details.

IgnoreSelected true|false

If set to true, inverts the selection made by Value, i. e. all matching values will be ignored.

### Plugin "python"
This plugin embeds a Python-interpreter into collectd and provides an interface to collectd's plugin system. See collectd-python(5) for its documentation.

### Plugin "redfish"
The "redfish" plugin collects sensor data using REST protocol called Redfish.

Sample configuration:

```
  <Plugin redfish>
    <Query "fans">
      Endpoint "/redfish/v1/Chassis/Chassis-1/Thermal"
      <Resource "Fans">
        <Property "ReadingRPM">
          PluginInstance "chassis-1"
          Type "rpm"
        </Property>
      </Resource>
    </Query>
    <Query "temperatures">
      Endpoint "/redfish/v1/Chassis/Chassis-1/Thermal"
      <Resource "Temperatures">
        <Property "ReadingCelsius">
          PluginInstance "chassis-1"
          Type "degrees"
        </Property>
      </Resource>
    </Query>
    <Query "voltages">
      Endpoint "/redfish/v1/Chassis/Chassis-1/Power"
      <Resource "Voltages">
        <Property "ReadingVolts">
          PluginInstance "chassis-1"
          Type "volts"
        </Property>
      </Resource>
    </Query>
    <Service "local">
      Host "127.0.0.1:5000"
      User "user"
      Passwd "passwd"
      Queries "fans" "voltages" "temperatures"
    </Service>
  </Plugin>
```

Query

Section defining a query performed on Redfish interface

Endpoint

URI of the REST API Endpoint for accessing the BMC

Resource

Selects single resource or array to collect data.

Property

Selects property from which data is gathered

PluginInstance

Plugin instance of dispatched collectd metric

Type

Type of dispatched collectd metric

TypeInstance

Type instance of collectd metric

Service

Section defining service to be sent requests

Username

BMC username

Password

BMC password

Queries

Queries to run

### Plugin "routeros"
The "routeros" plugin connects to a device running RouterOS, the Linux-based operating system for routers by MikroTik. The plugin uses librouteros to connect and reads information about the interfaces and wireless connections of the device. The configuration supports querying multiple routers:

```
  <Plugin "routeros">
    <Router>
      Host "router0.example.com"
      User "collectd"
      Password "secr3t"
      CollectInterface true
      CollectCPULoad true
      CollectMemory true
    </Router>
    <Router>
      Host "router1.example.com"
      User "collectd"
      Password "5ecret"
      CollectInterface true
      CollectRegistrationTable true
      CollectDF true
      CollectDisk true
      CollectHealth true
    </Router>
  </Plugin>
```

As you can see above, the configuration of the routeros plugin consists of one or more <Router> blocks. Within each block, the following options are understood:

Host Host

Hostname or IP-address of the router to connect to.

Port Port

Port name or port number used when connecting. If left unspecified, the default will be chosen by librouteros, currently "8728". This option expects a string argument, even when a numeric port number is given.

User User

Use the user name User to authenticate. Defaults to "admin".

Password Password

Set the password used to authenticate.

CollectInterface true|false

When set to true, interface statistics will be collected for all interfaces present on the device. Defaults to false.

CollectRegistrationTable true|false

When set to true, information about wireless LAN connections will be collected. Defaults to false.

CollectCPULoad true|false

When set to true, information about the CPU usage will be collected. The number is a dimensionless value where zero indicates no CPU usage at all. Defaults to false.

CollectMemory true|false

When enabled, the amount of used and free memory will be collected. How used memory is calculated is unknown, for example whether or not caches are counted as used space. Defaults to false.

CollectDF true|false

When enabled, the amount of used and free disk space will be collected. Defaults to false.

CollectDisk true|false

When enabled, the number of sectors written and bad blocks will be collected. Defaults to false.

CollectHealth true|false

When enabled, the health statistics will be collected. This includes the voltage and temperature on supported hardware. Defaults to false.

### Plugin "redis"
The Redis plugin connects to one or more Redis servers, gathers information about each server's state and executes user-defined queries. For each server there is a Node block which configures the connection parameters and set of user-defined queries for this node.

```
  <Plugin redis>
    <Node "example">
        Host "localhost"
        Port "6379"
        #Socket "/var/run/redis/redis.sock"
        Timeout 2000
        ReportCommandStats false
        ReportCpuUsage true
        <Query "LLEN myqueue">
          #Database 0
          Type "queue_length"
          Instance "myqueue"
        </Query>
    </Node>
  </Plugin>
```

Node Nodename

The Node block identifies a new Redis node, that is a new Redis instance running in an specified host and port. The name for node is a canonical identifier which is used as plugin instance. It is limited to 128 characters in length. When no Node is configured explicitly, plugin connects to "localhost:6379".

Host Hostname

The Host option is the hostname or IP-address where the Redis instance is running on.

Port Port

The Port option is the TCP port on which the Redis instance accepts connections. Either a service name of a port number may be given. Please note that numerical port numbers must be given as a string, too.

Socket Path

Connect to Redis using the UNIX domain socket at Path. If this setting is given, the Hostname and Port settings are ignored.

Password Password

Use Password to authenticate when connecting to Redis.

Timeout Milliseconds

The Timeout option set the socket timeout for node response. Since the Redis read function is blocking, you should keep this value as low as possible. It is expected what Timeout values should be lower than Interval defined globally. Defaults to 2000 (2 seconds).

ReportCommandStats false|true

Enables or disables reporting of statistics based on the command type, including rate of command calls and average CPU time consumed by command processing. Defaults to false.

ReportCpuUsage true|false

Enables or disables reporting of CPU consumption statistics. Defaults to true.

Query Querystring

The Query block identifies a query to execute against the redis server. There may be an arbitrary number of queries to execute. Each query should return single string or integer.

Type Collectd type

Within a query definition, a valid collectd type to use as when submitting the result of the query. When not supplied, will default to gauge. Currently only types with one datasource are supported. See types.db(5) for more details on types and their configuration.

Instance Type instance

Within a query definition, an optional type instance to use when submitting the result of the query. When not supplied will default to the escaped command, up to 128 chars.

Database Index

This index selects the Redis logical database to use for query. Defaults to 0.

### Plugin "rrdcached"
The "rrdcached" plugin uses the RRDtool accelerator daemon, rrdcached(1), to store values to RRD files in an efficient manner. The combination of the "rrdcached" plugin and the "rrdcached" daemon is very similar to the way the "rrdtool" plugin works (see below). The added abstraction layer provides a number of benefits, though: Because the cache is not within "collectd" anymore, it does not need to be flushed when "collectd" is to be restarted. This results in much shorter (if any) gaps in graphs, especially under heavy load. Also, the "rrdtool" command line utility is aware of the daemon so that it can flush values to disk automatically when needed. This allows one to integrate automated flushing of values into graphing solutions much more easily.

There are disadvantages, though: The daemon may reside on a different host, so it may not be possible for "collectd" to create the appropriate RRD files anymore. And even if "rrdcached" runs on the same host, it may run in a different base directory, so relative paths may do weird stuff if you're not careful.

So the recommended configuration is to let "collectd" and "rrdcached" run on the same host, communicating via a UNIX domain socket. The DataDir setting should be set to an absolute path, so that a changed base directory does not result in RRD files being created / expected in the wrong place.

DaemonAddress Address

Address of the daemon as understood by the "rrdc_connect" function of the RRD library. See rrdcached(1) for details. Example:

```
  <Plugin "rrdcached">
    DaemonAddress "unix:/var/run/rrdcached.sock"
  </Plugin>

```

DataDir Directory

Set the base directory in which the RRD files reside. If this is a relative path, it is relative to the working base directory of the "rrdcached" daemon! Use of an absolute path is recommended.

CreateFiles true|false

Enables or disables the creation of RRD files. If the daemon is not running locally, or DataDir is set to a relative path, this will not work as expected. Default is true.

CreateFilesAsync false|true

When enabled, new RRD files are enabled asynchronously, using a separate thread that runs in the background. This prevents writes to block, which is a problem especially when many hundreds of files need to be created at once. However, since the purpose of creating the files asynchronously is not to block until the file is available, values before the file is available will be discarded. When disabled (the default) files are created synchronously, blocking for a short while, while the file is being written.

StepSize Seconds

Force the stepsize of newly created RRD-files. Ideally (and per default) this setting is unset and the stepsize is set to the interval in which the data is collected. Do not use this option unless you absolutely have to for some reason. Setting this option may cause problems with the "snmp plugin", the "exec plugin" or when the daemon is set up to receive data from other hosts.

HeartBeat Seconds

Force the heartbeat of newly created RRD-files. This setting should be unset in which case the heartbeat is set to twice the StepSize which should equal the interval in which data is collected. Do not set this option unless you have a very good reason to do so.

RRARows NumRows

The "rrdtool plugin" calculates the number of PDPs per CDP based on the StepSize, this setting and a timespan. This plugin creates RRD-files with three times five RRAs, i. e. five RRAs with the CFs MIN, AVERAGE, and MAX. The five RRAs are optimized for graphs covering one hour, one day, one week, one month, and one year. So for each timespan, it calculates how many PDPs need to be consolidated into one CDP by calculating:

number of PDPs = timespan / (stepsize * rrarows)

Bottom line is, set this no smaller than the width of you graphs in pixels. The default is 1200.

RRATimespan Seconds

Adds an RRA-timespan, given in seconds. Use this option multiple times to have more then one RRA. If this option is never used, the built-in default of (3600, 86400, 604800, 2678400, 31622400) is used. For more information on how RRA-sizes are calculated see RRARows above.

XFF Factor

Set the "XFiles Factor". The default is 0.1. If unsure, don't set this option. Factor must be in the range "[0.0-1.0)", i.e. between zero (inclusive) and one (exclusive).

CollectStatistics false|true

When set to true, various statistics about the rrdcached daemon will be collected, with "rrdcached" as the plugin name. Defaults to false. Statistics are read via rrdcacheds socket using the STATS command. See rrdcached(1) for details.

### Plugin "rrdtool"
You can use the settings StepSize, HeartBeat, RRARows, and XFF to fine-tune your RRD-files. Please read rrdcreate(1) if you encounter problems using these settings. If you don't want to dive into the depths of RRDtool, you can safely ignore these settings.

DataDir Directory

Set the directory to store RRD files under. By default RRD files are generated beneath the daemon's working directory, i.e. the BaseDir.

CreateFilesAsync false|true

When enabled, new RRD files are enabled asynchronously, using a separate thread that runs in the background. This prevents writes to block, which is a problem especially when many hundreds of files need to be created at once. However, since the purpose of creating the files asynchronously is not to block until the file is available, values before the file is available will be discarded. When disabled (the default) files are created synchronously, blocking for a short while, while the file is being written.

StepSize Seconds

Force the stepsize of newly created RRD-files. Ideally (and per default) this setting is unset and the stepsize is set to the interval in which the data is collected. Do not use this option unless you absolutely have to for some reason. Setting this option may cause problems with the "snmp plugin", the "exec plugin" or when the daemon is set up to receive data from other hosts.

HeartBeat Seconds

Force the heartbeat of newly created RRD-files. This setting should be unset in which case the heartbeat is set to twice the StepSize which should equal the interval in which data is collected. Do not set this option unless you have a very good reason to do so.

RRARows NumRows

The "rrdtool plugin" calculates the number of PDPs per CDP based on the StepSize, this setting and a timespan. This plugin creates RRD-files with three times five RRAs, i.e. five RRAs with the CFs MIN, AVERAGE, and MAX. The five RRAs are optimized for graphs covering one hour, one day, one week, one month, and one year. So for each timespan, it calculates how many PDPs need to be consolidated into one CDP by calculating:

number of PDPs = timespan / (stepsize * rrarows)

Bottom line is, set this no smaller than the width of you graphs in pixels. The default is 1200.

RRATimespan Seconds

Adds an RRA-timespan, given in seconds. Use this option multiple times to have more then one RRA. If this option is never used, the built-in default of (3600, 86400, 604800, 2678400, 31622400) is used. For more information on how RRA-sizes are calculated see RRARows above.

XFF Factor

Set the "XFiles Factor". The default is 0.1. If unsure, don't set this option. Factor must be in the range "[0.0-1.0)", i.e. between zero (inclusive) and one (exclusive).

CacheFlush Seconds

When the "rrdtool" plugin uses a cache (by setting CacheTimeout, see below) it writes all values for a certain RRD-file if the oldest value is older than (or equal to) the number of seconds specified by CacheTimeout. That check happens on new values arriwal. If some RRD-file is not updated anymore for some reason (the computer was shut down, the network is broken, etc.) some values may still be in the cache. If CacheFlush is set, then every Seconds seconds the entire cache is searched for entries older than CacheTimeout + RandomTimeout seconds. The entries found are written to disk. Since scanning the entire cache is kind of expensive and does nothing under normal circumstances, this value should not be too small. 900 seconds might be a good value, though setting this to 7200 seconds doesn't normally do much harm either. Defaults to 10x CacheTimeout. CacheFlush must be larger than or equal to CacheTimeout, otherwise the above default is used.

CacheTimeout Seconds

If this option is set to a value greater than zero, the "rrdtool plugin" will save values in a cache, as described above. Writing multiple values at once reduces IO-operations and thus lessens the load produced by updating the files. The trade off is that the graphs kind of "drag behind" and that more memory is used.

WritesPerSecond Updates

When collecting many statistics with collectd and the "rrdtool" plugin, you will run serious performance problems. The CacheFlush setting and the internal update queue assert that collectd continues to work just fine even under heavy load, but the system may become very unresponsive and slow. This is a problem especially if you create graphs from the RRD files on the same machine, for example using the "graph.cgi" script included in the "contrib/collection3/" directory. This setting is designed for very large setups. Setting this option to a value between 25 and 80 updates per second, depending on your hardware, will leave the server responsive enough to draw graphs even while all the cached values are written to disk. Flushed values, i. e. values that are forced to disk by the FLUSH command, are not effected by this limit. They are still written as fast as possible, so that web frontends have up to date data when generating graphs.

For example: If you have 100,000 RRD files and set WritesPerSecond to 30 updates per second, writing all values to disk will take approximately 56 minutes. Together with the flushing ability that's integrated into "collection3" you'll end up with a responsive and fast system, up to date graphs and basically a "backup" of your values every hour.

RandomTimeout Seconds

When set, the actual timeout for each value is chosen randomly between CacheTimeout-RandomTimeout and CacheTimeout+RandomTimeout. The intention is to avoid high load situations that appear when many values timeout at the same time. This is especially a problem shortly after the daemon starts, because all values were added to the internal cache at roughly the same time.

### Plugin "sensors"
The Sensors plugin uses lm_sensors to retrieve sensor-values. This means that all the needed modules have to be loaded and lm_sensors has to be configured (most likely by editing /etc/sensors.conf. Read sensors.conf(5) for details.

The lm_sensors homepage can be found at <http://secure.netroedge.com/~lm78/>.

SensorConfigFile File

Read the lm_sensors configuration from File. When unset (recommended), the library's default will be used.

Sensor chip-bus-address/type-feature

Selects the name of the sensor which you want to collect or ignore, depending on the IgnoreSelected below. For example, the option "Sensor it8712-isa-0290/voltage-in1" will cause collectd to gather data for the voltage sensor in1 of the it8712 on the isa bus at the address 0290. The value passed to this option has the format "plugin_instance/type-type_instance".

See /"IGNORELISTS" for details.

IgnoreSelected true|false

If no configuration if given, the sensors-plugin will collect data from all sensors. This may not be practical, especially for uninteresting sensors. Thus, you can use the Sensor-option to pick the sensors you're interested in. Sometimes, however, it's easier/preferred to collect all sensors except a few ones. This option enables you to do that: By setting IgnoreSelected to true the effect of Sensor is inverted: All selected sensors are ignored and all other sensors are collected.

UseLabels true|false

Configures how sensor readings are reported. When set to true, sensor readings are reported using their descriptive label (e.g. "VCore"). When set to false (the default) the sensor name is used ("in0").

### Plugin "sigrok"
The sigrok plugin uses libsigrok to retrieve measurements from any device supported by the sigrok <http://sigrok.org/> project.

Synopsis

```
 <Plugin sigrok>
   LogLevel 3
   <Device "AC Voltage">
      Driver "fluke-dmm"
      MinimumInterval 10
      Conn "/dev/ttyUSB2"
   </Device>
   <Device "Sound Level">
      Driver "cem-dt-885x"
      Conn "/dev/ttyUSB1"
   </Device>
 </Plugin>
```

LogLevel 0-5

The sigrok logging level to pass on to the collectd log, as a number between 0 and 5 (inclusive). These levels correspond to "None", "Errors", "Warnings", "Informational", "Debug "and "Spew", respectively. The default is 2 ("Warnings"). The sigrok log messages, regardless of their level, are always submitted to collectd at its INFO log level.

<Device Name>

A sigrok-supported device, uniquely identified by this section's options. The Name is passed to collectd as the plugin instance.

Driver DriverName

The sigrok driver to use for this device.

Conn ConnectionSpec

If the device cannot be auto-discovered, or more than one might be discovered by the driver, ConnectionSpec specifies the connection string to the device. It can be of the form of a device path (e.g. "/dev/ttyUSB2"), or, in case of a non-serial USB-connected device, the USB VendorID.ProductID separated by a period (e.g. 0403.6001). A USB device can also be specified as Bus.Address (e.g. 1.41).

SerialComm SerialSpec

For serial devices with non-standard port settings, this option can be used to specify them in a form understood by sigrok, e.g. "9600/8n1". This should not be necessary; drivers know how to communicate with devices they support.

MinimumInterval Seconds

Specifies the minimum time between measurement dispatches to collectd, in seconds. Since some sigrok supported devices can acquire measurements many times per second, it may be necessary to throttle these. For example, the RRD plugin cannot process writes more than once per second. The default MinimumInterval is 0, meaning measurements received from the device are always dispatched to collectd. When throttled, unused measurements are discarded.

### Plugin "slurm"
This plugin collects per-partition SLURM node and job state information, as well as internal health statistics. It takes no options. It should run on a node that is capable of running the sinfo and squeue commands, i.e. it has a running slurmd and a valid slurm.conf. Note that this plugin needs the Globals option set to true in order to function properly.

### Plugin "smart"
The "smart" plugin collects SMART information from physical disks. Values collectd include temperature, power cycle count, poweron time and bad sectors. Also, all SMART attributes are collected along with the normalized current value, the worst value, the threshold and a human readable value. The plugin can also collect SMART attributes for NVMe disks (present in accordance with NVMe 1.4 spec) and Additional SMART Attributes from IntelX NVMe disks.

Using the following two options you can ignore some disks or configure the collection only of specific disks.

Disk Name

Select the disk Name. Whether it is collected or ignored depends on the IgnoreSelected setting, see below. As with other plugins that use the daemon's ignorelist functionality, a string that starts and ends with a slash is interpreted as a regular expression. Examples:

```
  Disk "sdd"
  Disk "/hda[34]/"
  Disk "nvme0n1"

```

See /"IGNORELISTS" for details.

IgnoreSelected true|false

Sets whether selected disks, i. e. the ones matches by any of the Disk statements, are ignored or if all other disks are ignored. The behavior (hopefully) is intuitive: If no Disk option is configured, all disks are collected. If at least one Disk option is given and no IgnoreSelected or set to false, only matching disks will be collected. If IgnoreSelected is set to true, all disks are collected except the ones matched.

IgnoreSleepMode true|false

Normally, the "smart" plugin will ignore disks that are reported to be asleep. This option disables the sleep mode check and allows the plugin to collect data from these disks anyway. This is useful in cases where libatasmart mistakenly reports disks as asleep because it has not been updated to incorporate support for newer idle states in the ATA spec.

UseSerial true|false

A disk's kernel name (e.g., sda) can change from one boot to the next. If this option is enabled, the "smart" plugin will use the disk's serial number (e.g., HGST_HUH728080ALE600_2EJ8VH8X) instead of the kernel name as the key for storing data. This ensures that the data for a given disk will be kept together even if the kernel name changes.

### Plugin "snmp"
Since the configuration of the "snmp plugin" is a little more complicated than other plugins, its documentation has been moved to an own manpage, collectd-snmp(5). Please see there for details.

### Plugin "snmp_agent"
The snmp_agent plugin is an AgentX subagent that receives and handles queries from SNMP master agent and returns the data collected by read plugins. The snmp_agent plugin handles requests only for OIDs specified in configuration file. To handle SNMP queries the plugin gets data from collectd and translates requested values from collectd's internal format to SNMP format. This plugin is a generic plugin and cannot work without configuration. For more details on AgentX subagent see <http://www.net-snmp.org/tutorial/tutorial-5/toolkit/demon/>

Synopsis:

```
  <Plugin snmp_agent>
    <Data "memAvailReal">
      Plugin "memory"
      #PluginInstance "some"
      Type "memory"
      TypeInstance "free"
      OIDs "1.3.6.1.4.1.2021.4.6.0"
    </Data>
    <Table "ifTable">
      IndexOID "IF-MIB::ifIndex"
      SizeOID "IF-MIB::ifNumber"
      <Data "ifDescr">
        <IndexKey>
          Source "PluginInstance"
        </IndexKey>
        Plugin "interface"
        OIDs "IF-MIB::ifDescr"
      </Data>
      <Data "ifOctets">
        Plugin "interface"
        Type "if_octets"
        TypeInstance ""
        OIDs "IF-MIB::ifInOctets" "IF-MIB::ifOutOctets"
      </Data>
    </Table>
    <Table "CPUAffinityTable">
      <Data "DomainName">
        <IndexKey>
          Source "PluginInstance"
        </IndexKey>
        Plugin "virt"
        OIDs "LIBVIRT-HYPERVISOR-MIB::lvhAffinityDomainName"
      </Data>
      <Data "VCPU">
        Plugin "virt"
        <IndexKey>
          Source "TypeInstance"
          Regex "^vcpu_([0-9]{1,3})-cpu_[0-9]{1,3}$"
          Group 1
        </IndexKey>
        OIDs "LIBVIRT-HYPERVISOR-MIB::lvhVCPUIndex"
      </Data>
      <Data "CPU">
        Plugin "virt"
        <IndexKey>
          Source "TypeInstance"
          Regex "^vcpu_[0-9]{1,3}-cpu_([0-9]{1,3})$"
          Group 1
        </IndexKey>
        OIDs "LIBVIRT-HYPERVISOR-MIB::lvhCPUIndex"
      </Data>
      <Data "CPUAffinity">
        Plugin "virt"
        Type "cpu_affinity"
        OIDs "LIBVIRT-HYPERVISOR-MIB::lvhCPUAffinity"
      </Data>
    </Table>
  </Plugin>
```

There are two types of blocks that can be contained in the "<Plugin snmp_agent>" block: Data and Table:

Data block

The Data block defines a list OIDs that are to be handled. This block can define scalar or table OIDs. If Data block is defined inside of Table block it reperesents table OIDs. The following options can be set:

IndexKey block

IndexKey block contains all data needed for proper index build of snmp table. In case more than one table Data block has IndexKey block present then multiple key index is built. If Data block defines scalar data type IndexKey has no effect and can be omitted.

Source String

Source can be set to one of the following values: "Hostname", "Plugin", "PluginInstance", "Type", "TypeInstance". This value indicates which field of corresponding collectd metric is taken as a SNMP table index.

Regex String

Regex option can also be used to parse strings or numbers out of specific field. For example: type-instance field which is "vcpu1-cpu2" can be parsed into two numeric fields CPU = 2 and VCPU = 1 and can be later used as a table index.

Group Number

Group number can be specified in case groups are used in regex.

Plugin String

Read plugin name whose collected data will be mapped to specified OIDs.

PluginInstance String

Read plugin instance whose collected data will be mapped to specified OIDs. The field is optional and by default there is no plugin instance check. Allowed only if Data block defines scalar data type.

Type String

Collectd's type that is to be used for specified OID, e. g. "if_octets" for example. The types are read from the TypesDB (see collectd.conf(5)).

TypeInstance String

Collectd's type-instance that is to be used for specified OID.

OIDs OID [OID ...]

Configures the OIDs to be handled by snmp_agent plugin. Values for these OIDs are taken from collectd data type specified by Plugin, PluginInstance, Type, TypeInstance fields of this Data block. Number of the OIDs configured should correspond to number of values in specified Type. For example two OIDs "IF-MIB::ifInOctets" "IF-MIB::ifOutOctets" can be mapped to "rx" and "tx" values of "if_octets" type.

Scale Value

The values taken from collectd are multiplied by Value. The field is optional and the default is 1.0.

Shift Value

Value is added to values from collectd after they have been multiplied by Scale value. The field is optional and the default value is 0.0.

The Table block

The Table block defines a collection of Data blocks that belong to one snmp table. In addition to multiple Data blocks the following options can be set:

IndexOID OID

OID that is handled by the plugin and is mapped to numerical index value that is generated by the plugin for each table record.

SizeOID OID

OID that is handled by the plugin. Returned value is the number of records in the table. The field is optional.

### Plugin "statsd"
The statsd plugin listens to a UDP socket, reads "events" in the statsd protocol and dispatches rates or other aggregates of these numbers periodically.

The plugin implements the Counter, Timer, Gauge and Set types which are dispatched as the collectd types "derive", "latency", "gauge" and "objects" respectively.

The following configuration options are valid:

Host Host

Bind to the hostname / address Host. By default, the plugin will bind to the "any" address, i.e. accept packets sent to any of the hosts addresses.

Port Port

UDP port to listen to. This can be either a service name or a port number. Defaults to 8125.

DeleteCounters false|true

DeleteTimers false|true

DeleteGauges false|true

DeleteSets false|true

These options control what happens if metrics are not updated in an interval. If set to False, the default, metrics are dispatched unchanged, i.e. the rate of counters and size of sets will be zero, timers report "NaN" and gauges are unchanged. If set to True, the such metrics are not dispatched and removed from the internal cache.

CounterSum false|true

When enabled, creates a "count" metric which reports the change since the last read. This option primarily exists for compatibility with the statsd implementation by Etsy.

TimerPercentile Percent

Calculate and dispatch the configured percentile, i.e. compute the latency, so that Percent of all reported timers are smaller than or equal to the computed latency. This is useful for cutting off the long tail latency, as it's often done in Service Level Agreements (SLAs). Different percentiles can be calculated by setting this option several times. If none are specified, no percentiles are calculated / dispatched.

TimerLower false|true

TimerUpper false|true

TimerSum false|true

TimerCount false|true

Calculate and dispatch various values out of Timer metrics received during an interval. If set to False, the default, these values aren't calculated / dispatched. Please note what reported timer values less than 0.001 are ignored in all Timer* reports.

### Plugin "swap"
The Swap plugin collects information about used and available swap space. On Linux and Solaris, the following options are available:

ReportByDevice false|true

Configures how to report physical swap devices. If set to false (the default), the summary over all swap devices is reported only, i.e. the globally used and available space over all devices. If true is configured, the used and available space of each device will be reported separately. This option is only available if the Swap plugin can read "/proc/swaps" (under Linux) or use the swapctl(2) mechanism (under Solaris).

ReportBytes false|true

When enabled, the swap I/O is reported in bytes. When disabled, the default, swap I/O is reported in pages. This option is available under Linux only.

ValuesAbsolute true|false

Enables or disables reporting of absolute swap metrics, i.e. number of bytes available and used. Defaults to true.

ValuesPercentage false|true

Enables or disables reporting of relative swap metrics, i.e. percent available and free. Defaults to false. This is useful for deploying collectd in a heterogeneous environment, where swap sizes differ and you want to specify generic thresholds or similar.

ReportIO true|false

Enables or disables reporting swap IO. Defaults to true. This is useful for the cases when swap IO is not neccessary, is not available, or is not reliable.

### Plugin "sysevent"
The sysevent plugin monitors rsyslog messages.

Synopsis:

```
  <Plugin sysevent>
    Listen "192.168.0.2" "6666"
    BufferSize 1024
    BufferLength 10
    RegexFilter "regex"
  </Plugin>
  rsyslog should be configured such that it sends data to the IP and port you
  include in the plugin configuration.  For example, given the configuration
  above, something like this would be set in /etc/rsyslog.conf:
    if $programname != 'collectd' then
    *.* @192.168.0.2:6666
  This plugin is designed to consume JSON rsyslog data, so a more complete
  rsyslog configuration would look like so (where we define a JSON template
  and use it when sending data to our IP and port):
    $template ls_json,"{%timestamp:::date-rfc3339,jsonf:@timestamp%, \
    %source:::jsonf:@source_host%,\"@source\":\"syslog://%fromhost-ip:::json%\", \
    \"@message\":\"%timestamp% %app-name%:%msg:::json%\",\"@fields\": \
    {%syslogfacility-text:::jsonf:facility%,%syslogseverity:::jsonf:severity-num%, \
    %syslogseverity-text:::jsonf:severity%,%programname:::jsonf:program%, \
    %procid:::jsonf:processid%}}"
    if $programname != 'collectd' then
    *.* @192.168.0.2:6666;ls_json
  Please note that these rsyslog.conf examples are *not* complete, as rsyslog
  requires more than these options in the configuration file.  These examples
  are meant to demonstration the proper remote logging and JSON format syntax.
```

Options:

Listen host port

Listen on this IP on this port for incoming rsyslog messages.

BufferSize length

Maximum allowed size for incoming rsyslog messages. Messages that exceed this number will be truncated to this size. Default is 4096 bytes.

BufferLength length

Maximum number of rsyslog events that can be stored in plugin's ring buffer. By default, this is set to 10. Once an event has been read, its location becomes available for storing a new event.

RegexFilter regex

Enumerate a regex filter to apply to all incoming rsyslog messages. If a message matches this filter, it will be published.

### Plugin "syslog"
LogLevel debug|info|notice|warning|err

Sets the log-level. If, for example, set to notice, then all events with severity notice, warning, or err will be submitted to the syslog-daemon. Please note that debug is only available if collectd has been compiled with debugging support.

NotifyLevel OKAY|WARNING|FAILURE

Controls which notifications should be sent to syslog. The default behaviour is not to send any. Less severe notifications always imply logging more severe notifications: Setting this to OKAY means all notifications will be sent to syslog, setting this to WARNING will send WARNING and FAILURE notifications but will dismiss OKAY notifications. Setting this option to FAILURE will only send failures to syslog.

### Plugin "table"
The "table plugin" provides generic means to parse tabular data and dispatch user specified values. Values are selected based on column numbers. For example, this plugin may be used to get values from the Linux proc(5) filesystem or CSV (comma separated values) files.

```
  <Plugin table>
    <Table "/proc/slabinfo">
      #Plugin "slab"
      Instance "slabinfo"
      Separator " "
      <Result>
        Type gauge
        InstancePrefix "active_objs"
        InstancesFrom 0
        ValuesFrom 1
      </Result>
      <Result>
        Type gauge
        InstancePrefix "objperslab"
        InstancesFrom 0
        ValuesFrom 4
      </Result>
    </Table>
  </Plugin>
```

The configuration consists of one or more Table blocks, each of which configures one file to parse. Within each Table block, there are one or more Result blocks, which configure which data to select and how to interpret it.

The following options are available inside a Table block:

Plugin Plugin

If specified, Plugin is used as the plugin name when submitting values. Defaults to table.

Instance instance

If specified, instance is used as the plugin instance. If omitted, the filename of the table is used instead, with all special characters replaced with an underscore ("_").

Separator string

Any character of string is interpreted as a delimiter between the different columns of the table. A sequence of two or more contiguous delimiters in the table is considered to be a single delimiter, i. e. there cannot be any empty columns. The plugin uses the strtok_r(3) function to parse the lines of a table - see its documentation for more details. This option is mandatory. A horizontal tab, newline and carriage return may be specified by "\\t", "\\n" and "\\r" respectively. Please note that the double backslashes are required because of collectd's config parsing.

The following options are available inside a Result block:

Type type

Sets the type used to dispatch the values to the daemon. Detailed information about types and their configuration can be found in types.db(5). This option is mandatory.

InstancePrefix prefix

If specified, prepend prefix to the type instance. If omitted, only the InstancesFrom option is considered for the type instance.

InstancesFrom column0 [column1 ...]

If specified, the content of the given columns (identified by the column number starting at zero) will be used to create the type instance for each row. Multiple values (and the instance prefix) will be joined together with dashes (-) as separation character. If omitted, only the InstancePrefix option is considered for the type instance. The plugin itself does not check whether or not all built instances are different. ItXs your responsibility to assure that each is unique. This is especially true, if you do not specify InstancesFrom: You have to make sure that the table only contains one row.

If neither InstancePrefix nor InstancesFrom is given, the type instance will be empty.

ValuesFrom column0 [column1 ...]

Specifies the columns (identified by the column numbers starting at zero) whose content is used as the actual data for the data sets that are dispatched to the daemon. How many such columns you need is determined by the Type setting above. If you specify too many or not enough columns, the plugin will complain about that and no data will be submitted to the daemon. The plugin uses strtoll(3) and strtod(3) to parse counter and gauge values respectively, so anything supported by those functions is supported by the plugin as well. This option is mandatory.

### Plugin "tail"
The "tail plugin" follows logfiles, just like tail(1) does, parses each line and dispatches found values. What is matched can be configured by the user using (extended) regular expressions, as described in regex(7).

```
  <Plugin "tail">
    <File "/var/log/exim4/mainlog">
      Plugin "mail"
      Instance "exim"
      Interval 60
      <Match>
        Regex "S=([1-9][0-9]*)"
        DSType "CounterAdd"
        Type "ipt_bytes"
        Instance "total"
      </Match>
      <Match>
        Regex "\\<R=local_user\\>"
        ExcludeRegex "\\<R=local_user\\>.*mail_spool defer"
        DSType "CounterInc"
        Type "counter"
        Instance "local_user"
      </Match>
      <Match>
        Regex "l=([0-9]*\\.[0-9]*)"
        <DSType "Distribution">
          Percentile 99
          Bucket 0 100
          #BucketType "bucket"
        </DSType>
        Type "latency"
        Instance "foo"
      </Match>
    </File>
  </Plugin>
```

The config consists of one or more File blocks, each of which configures one logfile to parse. Within each File block, there are one or more Match blocks, which configure a regular expression to search for.

The Plugin and Instance options in the File block may be used to set the plugin name and instance respectively. So in the above example the plugin name "mail-exim" would be used.

These options are applied for all Match blocks that follow it, until the next Plugin or Instance option. This way you can extract several plugin instances from one logfile, handy when parsing syslog and the like.

The Interval option allows you to define the length of time between reads. If this is not set, the default Interval will be used.

Each Match block has the following options to describe how the match should be performed:

Regex regex

Sets the regular expression to use for matching against a line. The first subexpression has to match something that can be turned into a number by strtoll(3) or strtod(3), depending on the value of "CounterAdd", see below. Because extended regular expressions are used, you do not need to use backslashes for subexpressions! If in doubt, please consult regex(7). Due to collectd's config parsing you need to escape backslashes, though. So if you want to match literal parentheses you need to do the following:

```
  Regex "SPAM \\(Score: (-?[0-9]+\\.[0-9]+)\\)"

```

ExcludeRegex regex

Sets an optional regular expression to use for excluding lines from the match. An example which excludes all connections from localhost from the match:

```
  ExcludeRegex "127\\.0\\.0\\.1"

```

DSType Type

Sets how the values are cumulated. Type is one of:

GaugeAverage

Calculate the average of all values matched during the interval.

GaugeMin

Report the smallest value matched during the interval.

GaugeMax

Report the greatest value matched during the interval.

GaugeLast

Report the last value matched during the interval.

GaugePersist

Report the last matching value. The metric is not reset to "NaN" at the end of an interval. It is continuously reported until another value is matched. This is intended for cases in which only state changes are reported, for example a thermometer that only reports the temperature when it changes.

CounterSet

DeriveSet

AbsoluteSet

The matched number is a counter. Simply sets the internal counter to this value. Variants exist for "COUNTER", "DERIVE", and "ABSOLUTE" data sources.

GaugeAdd

CounterAdd

DeriveAdd

Add the matched value to the internal counter. In case of DeriveAdd, the matched number may be negative, which will effectively subtract from the internal counter.

GaugeInc

CounterInc

DeriveInc

Increase the internal counter by one. These DSType are the only ones that do not use the matched subexpression, but simply count the number of matched lines. Thus, you may use a regular expression without submatch in this case. GaugeInc is reset to zero after every read, unlike other Gauge* metrics which are reset to "NaN".

Distribution

Type to do calculations based on the distribution of values, primarily calculating percentiles. This is primarily geared towards latency, but can be used for other metrics as well. The range of values tracked with this setting must be in the range (0X2^34) and can be fractional. Please note that neither zero nor 2^34 are inclusive bounds, i.e. zero cannot be handled by a distribution. This option must be used together with the Percentile and/or Bucket options.

Synopsis:

```
  <DSType "Distribution">
    Percentile 99
    Bucket 0 100
    BucketType "bucket"
  </DSType>

```

Percentile Percent

Calculate and dispatch the configured percentile, i.e. compute the value, so that Percent of all matched values are smaller than or equal to the computed latency. Metrics are reported with the type Type (the value of the above option) and the type instance "[<Instance>-]<Percent>".

This option may be repeated to calculate more than one percentile.

Bucket lower_bound upper_bound

Export the number of values (a "DERIVE") falling within the given range. Both, lower_bound and upper_bound may be a fractional number, such as 0.5. Each Bucket option specifies an interval "(lower_bound, upper_bound]", i.e. the range excludes the lower bound and includes the upper bound. lower_bound and upper_bound may be zero, meaning no lower/upper bound. To export the entire (0Xinf) range without overlap, use the upper bound of the previous range as the lower bound of the following range. In other words, use the following schema:

```
  Bucket   0   1
  Bucket   1   2
  Bucket   2   5
  Bucket   5  10
  Bucket  10  20
  Bucket  20  50
  Bucket  50   0

```

Metrics are reported with the type set by BucketType option ("bucket" by default) and the type instance "<Type>[-<Instance>]-<lower_bound>_<upper_bound>".

This option may be repeated to calculate more than one rate.

BucketType Type

Sets the type used to dispatch Bucket metrics. Optional, by default "bucket" will be used.

The Gauge* and Distribution types interpret the submatch as a floating point number, using strtod(3). The Counter* and AbsoluteSet types interpret the submatch as an unsigned integer using strtoull(3). The Derive* types interpret the submatch as a signed integer using strtoll(3). CounterInc, DeriveInc and GaugeInc do not use the submatch at all and it may be omitted in this case.

The Gauge* types, unless noted otherwise, are reset to "NaN" after being reported. In other words, GaugeAverage reports the average of all values matched since the last metric was reported (or "NaN" if there was no match).

Type Type

Sets the type used to dispatch this value. Detailed information about types and their configuration can be found in types.db(5).

Instance TypeInstance

This optional setting sets the type instance to use.

### Plugin "tail_csv"
The tail_csv plugin reads files in the CSV format, e.g. the statistics file written by Snort.

Synopsis:

```
 <Plugin "tail_csv">
   <Metric "snort-dropped">
       Type "percent"
       Instance "dropped"
       ValueFrom 1
   </Metric>
   <File "/var/log/snort/snort.stats">
       Plugin "snortstats"
       Instance "eth0"
       Interval 600
       Collect "snort-dropped"
       FieldSeparator ","
       #TimeFrom 0
   </File>
 </Plugin>
```

The configuration consists of one or more Metric blocks that define an index into the line of the CSV file and how this value is mapped to collectd's internal representation. These are followed by one or more Instance blocks which configure which file to read, in which interval and which metrics to extract.

<Metric Name>

The Metric block configures a new metric to be extracted from the statistics file and how it is mapped on collectd's data model. The string Name is only used inside the Instance blocks to refer to this block, so you can use one Metric block for multiple CSV files.

Type Type

Configures which Type to use when dispatching this metric. Types are defined in the types.db(5) file, see the appropriate manual page for more information on specifying types. Only types with a single data source are supported by the tail_csv plugin. The information whether the value is an absolute value (i.e. a "GAUGE") or a rate (i.e. a "DERIVE") is taken from the Type's definition.

Instance TypeInstance

If set, TypeInstance is used to populate the type instance field of the created value lists. Otherwise, no type instance is used.

ValueFrom Index

Configure to read the value from the field with the zero-based index Index. If the value is parsed as signed integer, unsigned integer or double depends on the Type setting, see above.

<File Path>

Each File block represents one CSV file to read. There must be at least one File block but there can be multiple if you have multiple CSV files.

Plugin Plugin

Use Plugin as the plugin name when submitting values. Defaults to "tail_csv".

Instance PluginInstance

Sets the plugin instance used when dispatching the values.

Collect Metric

Specifies which Metric to collect. This option must be specified at least once, and you can use this option multiple times to specify more than one metric to be extracted from this statistic file.

Interval Seconds

Configures the interval in which to read values from this instance / file. Defaults to the plugin's default interval.

TimeFrom Index

Rather than using the local time when dispatching a value, read the timestamp from the field with the zero-based index Index. The value is interpreted as seconds since epoch. The value is parsed as a double and may be factional.

FieldSeparator Character

Specify the character to use as field separator while parsing the CSV. Defaults to ',' if not specified. The value can only be a single character.

### Plugin "teamspeak2"
The "teamspeak2 plugin" connects to the query port of a teamspeak2 server and polls interesting global and virtual server data. The plugin can query only one physical server but unlimited virtual servers. You can use the following options to configure it:

Host hostname/ip

The hostname or ip which identifies the physical server. Default: 127.0.0.1

Port port

The query port of the physical server. This needs to be a string. Default: "51234"

Server port

This option has to be added once for every virtual server the plugin should query. If you want to query the virtual server on port 8767 this is what the option would look like:

```
  Server "8767"

```

This option, although numeric, needs to be a string, i. e. you must use quotes around it! If no such statement is given only global information will be collected.

### Plugin "ted"
The TED plugin connects to a device of "The Energy Detective", a device to measure power consumption. These devices are usually connected to a serial (RS232) or USB port. The plugin opens a configured device and tries to read the current energy readings. For more information on TED, visit <http://www.theenergydetective.com/>.

Available configuration options:

Device Path

Path to the device on which TED is connected. collectd will need read and write permissions on that file. Default: /dev/ttyUSB0

Retries Num

Apparently reading from TED is not that reliable. You can therefore configure a number of retries here. You only configure the retries here, to if you specify zero, one reading will be performed (but no retries if that fails); if you specify three, a maximum of four readings are performed. Negative values are illegal. Default: 0

### Plugin "tcpconns"
The "tcpconns plugin" counts the number of currently established TCP connections based on the local port and/or the remote port. Since there may be a lot of connections the default if to count all connections with a local port, for which a listening socket is opened. You can use the following options to fine-tune the ports you are interested in:

ListeningPorts true|false

If this option is set to true, statistics for all local ports for which a listening socket exists are collected. The default depends on LocalPort and RemotePort (see below): If no port at all is specifically selected, the default is to collect listening ports. If specific ports (no matter if local or remote ports) are selected, this option defaults to false, i. e. only the selected ports will be collected unless this option is set to true specifically.

LocalPort Port

Count the connections to a specific local port. This can be used to see how many connections are handled by a specific daemon, e. g. the mailserver. You have to specify the port in numeric form, so for the mailserver example you'd need to set 25.

RemotePort Port

Count the connections to a specific remote port. This is useful to see how much a remote service is used. This is most useful if you want to know how many connections a local service has opened to remote services, e. g. how many connections a mail server or news server has to other mail or news servers, or how many connections a web proxy holds to web servers. You have to give the port in numeric form.

AllPortsSummary true|false

If this option is set to true a summary of statistics from all connections are collected. This option defaults to false.

### Plugin "thermal"
ForceUseProcfs true|false

By default, the Thermal plugin tries to read the statistics from the Linux "sysfs" interface. If that is not available, the plugin falls back to the "procfs" interface. By setting this option to true, you can force the plugin to use the latter. This option defaults to false.

Device Device

Selects the name of the thermal device that you want to collect or ignore, depending on the value of the IgnoreSelected option. This option may be used multiple times to specify a list of devices. See /"IGNORELISTS" for details.

IgnoreSelected true|false

Invert the selection: If set to true, all devices except the ones that match the device names specified by the Device option are collected. By default only selected devices are collected if a selection is made. If no selection is configured at all, all devices are selected.

### Plugin "threshold"
The Threshold plugin checks values collected or received by collectd against a configurable threshold and issues notifications if values are out of bounds.

Documentation for this plugin is available in the collectd-threshold(5) manual page.

### Plugin "tokyotyrant"
The TokyoTyrant plugin connects to a TokyoTyrant server and collects a couple metrics: number of records, and database size on disk.

Host Hostname/IP

The hostname or IP which identifies the server. Default: 127.0.0.1

Port Service/Port

The query port of the server. This needs to be a string, even if the port is given in its numeric form. Default: 1978

### Plugin "turbostat"
The Turbostat plugin reads CPU frequency and C-state residency on modern Intel processors by using Model Specific Registers.

CoreCstates Bitmask(Integer)

Bit mask of the list of core C-states supported by the processor. This option should only be used if the automated detection fails. Default value extracted from the CPU model and family. Currently supported C-states (by this plugin): 3, 6, 7

Example:

```
  All states (3, 6 and 7):
  (1<<3) + (1<<6) + (1<<7) = 392

```

PackageCstates Bitmask(Integer)

Bit mask of the list of packages C-states supported by the processor. This option should only be used if the automated detection fails. Default value extracted from the CPU model and family. Currently supported C-states (by this plugin): 2, 3, 6, 7, 8, 9, 10

Example:

```
  States 2, 3, 6 and 7:
  (1<<2) + (1<<3) + (1<<6) + (1<<7) = 396

```

SystemManagementInterrupt true|false

Boolean enabling the collection of the I/O System-Management Interrupt counter. This option should only be used if the automated detection fails or if you want to disable this feature.

DigitalTemperatureSensor true|false

Boolean enabling the collection of the temperature of each core. This option should only be used if the automated detection fails or if you want to disable this feature.

TCCActivationTemp Temperature

Thermal Control Circuit Activation Temperature of the installed CPU. This temperature is used when collecting the temperature of cores or packages. This option should only be used if the automated detection fails. Default value extracted from MSR_IA32_TEMPERATURE_TARGET.

RunningAveragePowerLimit Bitmask(Integer)

Bit mask of the list of elements to be thermally monitored. This option should only be used if the automated detection fails or if you want to disable some collections. The different bits of this bit mask accepted by this plugin are:

- 0 ('1'): Package

- 1 ('2'): DRAM

- 2 ('4'): Cores

- 3 ('8'): Embedded graphic device

LogicalCoreNames true|false

Boolean enabling the use of logical core numbering for per core statistics. When enabled, "cpu<n>" is used as plugin instance, where n is a dynamic number assigned by the kernel. Otherwise, "core<n>" is used if there is only one package and "pkg<n>-core<m>" if there is more than one, where n is the n-th core of package m.

RestoreAffinityPolicy AllCPUs|Restore

Reading data from CPU has side-effect: collectd process's CPU affinity mask changes. After reading data is completed, affinity mask needs to be restored. This option allows to set restore policy. AllCPUs (the default): Restore the affinity by setting affinity to any/all CPUs.

Restore: Save affinity using sched_getaffinity() before reading data and restore it after.

On some systems, sched_getaffinity() will fail due to inconsistency of the CPU set size between userspace and kernel. In these cases plugin will detect the unsuccessful call and fail with an error, preventing data collection. Most of configurations does not need to save affinity as Collectd process is allowed to run on any/all available CPUs.

If you need to save and restore affinity and get errors like 'Unable to save the CPU affinity', setting 'possible_cpus' kernel boot option may also help.

See following links for details:

<https://github.com/collectd/collectd/issues/1593> <https://sourceware.org/bugzilla/show_bug.cgi?id=15630> <https://bugzilla.kernel.org/show_bug.cgi?id=151821>

### Plugin "ubi"
The Ubi plugin collects some statistics about the UBI (Unsorted Block Image). Values collected are the number of bad physical eraseblocks on the underlying MTD (Memory Technology Device) and the maximum erase counter value concerning one volume.

See following links for details:

<http://www.linux-mtd.infradead.org/doc/ubi.html> <http://www.linux-mtd.infradead.org/doc/ubifs.html> <https://www.kernel.org/doc/Documentation/ABI/stable/sysfs-class-ubi>

Device Name

Select the device Name of the UBI volume. Whether it is collected or ignored depends on the IgnoreSelected setting, see below. See /"IGNORELISTS" for details.

IgnoreSelected true|false

Sets whether selected devices, i. e. the ones matches by any of the Device statements, are ignored or if all other devices are ignored. If no Device option is configured, all devices are collected. If at least one Device is given and no IgnoreSelected or set to false, only matching disks will be collected. If IgnoreSelectedis set to true, all devices are collected except the ones matched.

### Plugin "unixsock"
SocketFile Path

Sets the socket-file which is to be created.

SocketGroup Group

If running as root change the group of the UNIX-socket after it has been created. Defaults to collectd.

SocketPerms Permissions

Change the file permissions of the UNIX-socket after it has been created. The permissions must be given as a numeric, octal value as you would pass to chmod(1). Defaults to 0770.

DeleteSocket false|true

If set to true, delete the socket file before calling bind(2), if a file with the given name already exists. If collectd crashes a socket file may be left over, preventing the daemon from opening a new socket when restarted. Since this is potentially dangerous, this defaults to false.

### Plugin "uuid"
This plugin, if loaded, causes the Hostname to be taken from the machine's UUID. The UUID is a universally unique designation for the machine, usually taken from the machine's BIOS. This is most useful if the machine is running in a virtual environment such as Xen, in which case the UUID is preserved across shutdowns and migration.

The following methods are used to find the machine's UUID, in order:

- Check /etc/uuid (or UUIDFile).

- Check for UUID from HAL (<http://www.freedesktop.org/wiki/Software/hal>) if present.

- Check for UUID from "dmidecode" / SMBIOS.

- Check for UUID from Xen hypervisor.

If no UUID can be found then the hostname is not modified.

UUIDFile Path

Take the UUID from the given file (default /etc/uuid).

### Plugin "varnish"
The varnish plugin collects information about Varnish, an HTTP accelerator. It collects a subset of the values displayed by varnishstat(1), and organizes them in categories which can be enabled or disabled. Currently only metrics shown in varnishstat(1)'s MAIN section are collected. The exact meaning of each metric can be found in varnish-counters(7).

Synopsis:

```
 <Plugin "varnish">
   <Instance "example">
     CollectBackend     true
     CollectBan         false
     CollectCache       true
     CollectConnections true
     CollectDirectorDNS false
     CollectESI         false
     CollectFetch       false
     CollectHCB         false
     CollectObjects     false
     CollectPurge       false
     CollectSession     false
     CollectSHM         true
     CollectSMA         false
     CollectSMS         false
     CollectSM          false
     CollectStruct      false
     CollectTotals      false
     CollectUptime      false
     CollectVCL         false
     CollectVSM         false
     CollectWorkers     false
     CollectLock        false
     CollectMempool     false
     CollectManagement  false
     CollectSMF         false
     CollectVBE         false
     CollectMSE         false
   </Instance>
 </Plugin>
```

The configuration consists of one or more <Instance Name> blocks. Name is the parameter passed to "varnishd -n". If left empty, it will collectd statistics from the default "varnishd" instance (this should work fine in most cases).

Inside each <Instance> blocks, the following options are recognized:

CollectBackend true|false

Back-end connection statistics, such as successful, reused, and closed connections. True by default.

CollectBan true|false

Statistics about ban operations, such as number of bans added, retired, and number of objects tested against ban operations. Only available with Varnish 3.x and above. False by default.

CollectCache true|false

Cache hits and misses. True by default.

CollectConnections true|false

Number of client connections received, accepted and dropped. True by default.

CollectDirectorDNS true|false

DNS director lookup cache statistics. Only available with Varnish 3.x. False by default.

CollectESI true|false

Edge Side Includes (ESI) parse statistics. False by default.

CollectFetch true|false

Statistics about fetches (HTTP requests sent to the backend). False by default.

CollectHCB true|false

Inserts and look-ups in the crit bit tree based hash. Look-ups are divided into locked and unlocked look-ups. False by default.

CollectObjects true|false

Statistics on cached objects: number of objects expired, nuked (prematurely expired), saved, moved, etc. False by default.

CollectPurge true|false

Statistics about purge operations, such as number of purges added, retired, and number of objects tested against purge operations. Only available with Varnish 2.x. False by default.

CollectSession true|false

Client session statistics. Number of past and current sessions, session herd and linger counters, etc. False by default. Note that if using Varnish 4.x, some metrics found in the Connections and Threads sections with previous versions of Varnish have been moved here.

CollectSHM true|false

Statistics about the shared memory log, a memory region to store log messages which is flushed to disk when full. True by default.

CollectSMA true|false

malloc or umem (umem_alloc(3MALLOC) based) storage statistics. The umem storage component is Solaris specific. Note: SMA, SMF and MSE share counters, enable only the one used by the Varnish instance. Available with Varnish 2.x, varnish 4.x and above (Not available in varnish 3.x). False by default.

CollectSMS true|false

synth (synthetic content) storage statistics. This storage component is used internally only. False by default.

CollectSM true|false

file (memory mapped file) storage statistics. Only available with Varnish 2.x, in varnish 4.x and above use CollectSMF. False by default.

CollectStruct true|false

Current varnish internal state statistics. Number of current sessions, objects in cache store, open connections to backends (with Varnish 2.x), etc. False by default.

CollectTotals true|false

Collects overview counters, such as the number of sessions created, the number of requests and bytes transferred. False by default.

CollectUptime true|false

Varnish uptime. Only available with Varnish 3.x and above. False by default.

CollectVCL true|false

Number of total (available + discarded) VCL (config files). False by default.

CollectVSM true|false

Collect statistics about Varnish's shared memory usage (used by the logging and statistics subsystems). Only available with Varnish 4.x. False by default.

CollectWorkers true|false

Collect statistics about worker threads. False by default.

CollectVBE true|false

Backend counters. Only available with Varnish 4.x and above. False by default.

CollectSMF true|false

file (memory mapped file) storage statistics. Only available with Varnish 4.x and above. Note: SMA, SMF and MSE share counters, enable only the one used by the Varnish instance. Used to be called SM in Varnish 2.x. False by default.

CollectManagement true|false

Management process counters. Only available with Varnish 4.x and above. False by default.

CollectLock true|false

Lock counters. Only available with Varnish 4.x and above. False by default.

CollectMempool true|false

Memory pool counters. Only available with Varnish 4.x and above. False by default.

CollectMSE true|false

Varnish Massive Storage Engine 2.0 (MSE2) is an improved storage backend for Varnish, replacing the traditional malloc and file storages. Only available with Varnish-Plus 4.x and above. Note: SMA, SMF and MSE share counters, enable only the one used by the Varnish instance. False by default.

CollectGOTO true|false

vmod-goto counters. Only available with Varnish Plus 6.x. False by default.

### Plugin "virt"
This plugin allows CPU, disk, network load and other metrics to be collected for virtualized guests on the machine. The statistics are collected through libvirt API (<http://libvirt.org/>). Majority of metrics can be gathered without installing any additional software on guests, especially collectd, which runs only on the host system.

Only Connection is required.

Consider the following example config:

```
 <Plugin "virt">
   Connection "qemu:///system"
   HostnameFormat "hostname"
   InterfaceFormat "address"
   PluginInstanceFormat "name"
 </Plugin>
```

It will generate the following values:

```
  node42.example.com/virt-instance-0006f26c/disk_octets-vda
  node42.example.com/virt-instance-0006f26c/disk_ops-vda
  node42.example.com/virt-instance-0006f26c/if_dropped-ca:fe:ca:fe:ca:fe
  node42.example.com/virt-instance-0006f26c/if_errors-ca:fe:ca:fe:ca:fe
  node42.example.com/virt-instance-0006f26c/if_octets-ca:fe:ca:fe:ca:fe
  node42.example.com/virt-instance-0006f26c/if_packets-ca:fe:ca:fe:ca:fe
  node42.example.com/virt-instance-0006f26c/memory-actual_balloon
  node42.example.com/virt-instance-0006f26c/memory-available
  node42.example.com/virt-instance-0006f26c/memory-last_update
  node42.example.com/virt-instance-0006f26c/memory-major_fault
  node42.example.com/virt-instance-0006f26c/memory-minor_fault
  node42.example.com/virt-instance-0006f26c/memory-rss
  node42.example.com/virt-instance-0006f26c/memory-swap_in
  node42.example.com/virt-instance-0006f26c/memory-swap_out
  node42.example.com/virt-instance-0006f26c/memory-total
  node42.example.com/virt-instance-0006f26c/memory-unused
  node42.example.com/virt-instance-0006f26c/memory-usable
  node42.example.com/virt-instance-0006f26c/virt_cpu_total
  node42.example.com/virt-instance-0006f26c/virt_vcpu-0
```

You can get information on the metric's units from the online libvirt documentation. For instance, virt_cpu_total is in nanoseconds.

Connection uri

Connect to the hypervisor given by uri. For example if using Xen use:

```
 Connection "xen:///"

```

Details which URIs allowed are given at <http://libvirt.org/uri.html>.

RefreshInterval seconds

Refresh the list of domains and devices every seconds. The default is 60 seconds. Setting this to be the same or smaller than the Interval will cause the list of domains and devices to be refreshed on every iteration. Refreshing the devices in particular is quite a costly operation, so if your virtualization setup is static you might consider increasing this. If this option is set to 0, refreshing is disabled completely.

Domain name

BlockDevice name:dev

InterfaceDevice name:dev

IgnoreSelected true|false

Select which domains and devices are collected. If IgnoreSelected is not given or false then only the listed domains and disk/network devices are collected.

If IgnoreSelected is true then the test is reversed and the listed domains and disk/network devices are ignored, while the rest are collected.

The domain name and device names may use a regular expression, if the name is surrounded by /.../ and collectd was compiled with support for regexps.

The default is to collect statistics for all domains and all their devices.

Note: BlockDevice and InterfaceDevice options are related to corresponding *Format options. Specifically, BlockDevice filtering depends on BlockDeviceFormat setting - if user wants to filter block devices by 'target' name then BlockDeviceFormat option has to be set to 'target' and BlockDevice option must be set to a valid block device target name("/:hdb/"). Mixing formats and filter values from different worlds (i.e., using 'target' name as BlockDevice value with BlockDeviceFormat set to 'source') may lead to unexpected results (all devices filtered out or all visible, depending on the value of IgnoreSelected option). Similarly, option InterfaceDevice is related to InterfaceFormat setting (i.e., when user wants to use MAC address as a filter then InterfaceFormat has to be set to 'address' - using wrong type here may filter out all of the interfaces).

Example 1:

Ignore all hdb devices on any domain, but other block devices (eg. hda) will be collected:

```
 BlockDevice "/:hdb/"
 IgnoreSelected "true"
 BlockDeviceFormat "target"

```

Example 2:

Collect metrics only for block device on 'baremetal0' domain when its 'source' matches given path:

```
 BlockDevice "baremetal0:/var/lib/libvirt/images/baremetal0.qcow2"
 BlockDeviceFormat source

```

As you can see it is possible to filter devices/interfaces using various formats - for block devices 'target' or 'source' name can be used. Interfaces can be filtered using 'name', 'address' or 'number'.

Example 3:

Collect metrics only for domains 'baremetal0' and 'baremetal1' and ignore any other domain:

```
 Domain "baremetal0"
 Domain "baremetal1"

```

It is possible to filter multiple block devices/domains/interfaces by adding multiple filtering entries in separate lines.

BlockDeviceFormat target|source

If BlockDeviceFormat is set to target, the default, then the device name seen by the guest will be used for reporting metrics. This corresponds to the "<target>" node in the XML definition of the domain. If BlockDeviceFormat is set to source, then metrics will be reported using the path of the source, e.g. an image file. This corresponds to the "<source>" node in the XML definition of the domain.

Example:

If the domain XML have the following device defined:

```
  <disk type='block' device='disk'>
    <driver name='qemu' type='raw' cache='none' io='native' discard='unmap'/>
    <source dev='/var/lib/libvirt/images/image1.qcow2'/>
    <target dev='sda' bus='scsi'/>
    <boot order='2'/>
    <address type='drive' controller='0' bus='0' target='0' unit='0'/>
  </disk>

```

Setting "BlockDeviceFormat target" will cause the type instance to be set to "sda". Setting "BlockDeviceFormat source" will cause the type instance to be set to "var_lib_libvirt_images_image1.qcow2".

Note: this option determines also what field will be used for filtering over block devices (filter value in BlockDevice will be applied to target or source). More info about filtering block devices can be found in the description of BlockDevice.

BlockDeviceFormatBasename false|true

The BlockDeviceFormatBasename controls whether the full path or the basename(1) of the source is being used as the type instance when BlockDeviceFormat is set to source. Defaults to false. Example:

Assume the device path (source tag) is "/var/lib/libvirt/images/image1.qcow2". Setting "BlockDeviceFormatBasename false" will cause the type instance to be set to "var_lib_libvirt_images_image1.qcow2". Setting "BlockDeviceFormatBasename true" will cause the type instance to be set to "image1.qcow2".

HostnameFormat name|uuid|hostname|metadata...

When the virt plugin logs data, it sets the hostname of the collected data according to this setting. The default is to use the guest name as provided by the hypervisor, which is equal to setting name. uuid means use the guest's UUID. This is useful if you want to track the same guest across migrations.

hostname means to use the global Hostname setting, which is probably not useful on its own because all guests will appear to have the same name. This is useful in conjunction with PluginInstanceFormat though.

metadata means use information from guest's metadata. Use HostnameMetadataNS and HostnameMetadataXPath to localize this information.

You can also specify combinations of these fields. For example name uuid means to concatenate the guest name and UUID (with a literal colon character between, thus "foo:1234-1234-1234-1234").

At the moment of writing (collectd-5.5), hostname string is limited to 62 characters. In case when combination of fields exceeds 62 characters, hostname will be truncated without a warning.

InterfaceFormat name|address|number

When the virt plugin logs interface data, it sets the name of the collected data according to this setting. The default is to use the path as provided by the hypervisor (the "dev" property of the target node), which is equal to setting name. address means use the interface's mac address. This is useful since the interface path might change between reboots of a guest or across migrations.

number means use the interface's number in guest.

Note: this option determines also what field will be used for filtering over interface device (filter value in InterfaceDevice will be applied to name, address or number). More info about filtering interfaces can be found in the description of InterfaceDevice.

PluginInstanceFormat name|uuid|metadata|none

When the virt plugin logs data, it sets the plugin_instance of the collected data according to this setting. The default is to not set the plugin_instance. name means use the guest's name as provided by the hypervisor. uuid means use the guest's UUID. metadata means use information from guest's metadata.

You can also specify combinations of the name and uuid fields. For example name uuid means to concatenate the guest name and UUID (with a literal colon character between, thus "foo:1234-1234-1234-1234").

HostnameMetadataNS string

When metadata is used in HostnameFormat or PluginInstanceFormat, this selects in which metadata namespace we will pick the hostname. The default is http://openstack.org/xmlns/libvirt/nova/1.0.

HostnameMetadataXPath string

When metadata is used in HostnameFormat or PluginInstanceFormat, this describes where the hostname is located in the libvirt metadata. The default is /instance/name/text().

ReportBlockDevices true|false

Enabled by default. Allows to disable stats reporting of block devices for whole plugin.

ReportNetworkInterfaces true|false

Enabled by default. Allows to disable stats reporting of network interfaces for whole plugin.

ExtraStats string

Report additional extra statistics. The default is no extra statistics, preserving the previous behaviour of the plugin. If unsure, leave the default. If enabled, allows the plugin to reported more detailed statistics about the behaviour of Virtual Machines. The argument is a space-separated list of selectors. Currently supported selectors are:

cpu_util: report CPU utilization per domain in percentage.

disk: report extra statistics like number of flush operations and total service time for read, write and flush operations. Requires libvirt API version 0.9.5 or later.

disk_err: report disk errors if any occured. Requires libvirt API version 0.9.10 or later.

domain_state: report domain state and reason as 'domain_state' metric.

fs_info: report file system information as a notification. Requires libvirt API version 1.2.11 or later. Can be collected only if Guest Agent is installed and configured inside VM. Make sure that installed Guest Agent version supports retrieving file system information.

job_stats_background: report statistics about progress of a background job on a domain. Only one type of job statistics can be collected at the same time. Requires libvirt API version 1.2.9 or later.

job_stats_completed: report statistics about a recently completed job on a domain. Only one type of job statistics can be collected at the same time. Requires libvirt API version 1.2.9 or later.

memory: report statistics about memory usage details, provided by libvirt virDomainMemoryStats() function.

pcpu: report the physical user/system cpu time consumed by the hypervisor, per-vm. Requires libvirt API version 0.9.11 or later.

perf: report performance monitoring events. To collect performance metrics they must be enabled for domain and supported by the platform. Requires libvirt API version 1.3.3 or later. Note: perf metrics can't be collected if intel_rdt plugin is enabled.

vcpu: report domain virtual CPUs utilisation.

vcpupin: report pinning of domain VCPUs to host physical CPUs.

disk_physical: report 'disk_physical' statistic for disk device. Note: This statistic is only reported for disk devices with 'source' property available.

disk_allocation: report 'disk_allocation' statistic for disk device. Note: This statistic is only reported for disk devices with 'source' property available.

disk_capacity: report 'disk_capacity' statistic for disk device. Note: This statistic is only reported for disk devices with 'source' property available.

PersistentNotification true|false

Override default configuration to only send notifications when there is a change in the lifecycle state of a domain. When set to true notifications will be sent for every read cycle. Default is false. Does not affect the stats being dispatched.

Instances integer

How many read instances you want to use for this plugin. The default is one, and the sensible setting is a multiple of the ReadThreads value. This option is only useful when domains are specially tagged. If you are not sure, just use the default setting.

The reader instance will only query the domains with attached matching tag. Tags should have the form of 'virt-X' where X is the reader instance number, starting from 0.

The special-purpose reader instance #0, guaranteed to be always present, will query all the domains with missing or unrecognized tag, so no domain will ever be left out.

Domain tagging is done with a custom attribute in the libvirt domain metadata section. Value is selected by an XPath /domain/metadata/ovirtmap/tag/text() expression in the http://ovirt.org/ovirtmap/tag/1.0 namespace. (XPath and namespace values are not configurable yet).

Tagging could be used by management applications to evenly spread the load among the reader threads, or to pin on the same threads all the libvirt domains which use the same shared storage, to minimize the disruption in presence of storage outages.

### Plugin "vmem"
The "vmem" plugin collects information about the usage of virtual memory. Since the statistics provided by the Linux kernel are very detailed, they are collected very detailed. However, to get all the details, you have to switch them on manually. Most people just want an overview over, such as the number of pages read from swap space.

Verbose true|false

Enables verbose collection of information. This will start collecting page "actions", e. g. page allocations, (de)activations, steals and so on. Part of these statistics are collected on a "per zone" basis.

### Plugin "vserver"
This plugin doesn't have any options. VServer support is only available for Linux. It cannot yet be found in a vanilla kernel, though. To make use of this plugin you need a kernel that has VServer support built in, i. e. you need to apply the patches and compile your own kernel, which will then provide the /proc/virtual filesystem that is required by this plugin.

The VServer homepage can be found at <http://linux-vserver.org/>.

Note: The traffic collected by this plugin accounts for the amount of traffic passing a socket which might be a lot less than the actual on-wire traffic (e. g. due to headers and retransmission). If you want to collect on-wire traffic you could, for example, use the logging facilities of iptables to feed data for the guest IPs into the iptables plugin.

### Plugin "write_graphite"
The "write_graphite" plugin writes data to Graphite, an open-source metrics storage and graphing project. The plugin connects to Carbon, the data layer of Graphite, via TCP or UDP and sends data via the "line based" protocol (per default using port 2003). The data will be sent in blocks of at most 1428 bytes to minimize the number of network packets.

Synopsis:

```
 <Plugin write_graphite>
   <Node "example">
     Host "localhost"
     Port "2003"
     Protocol "tcp"
     LogSendErrors true
     Prefix "collectd"
     UseTags false
     ReverseHost false
   </Node>
 </Plugin>
```

The configuration consists of one or more <Node Name> blocks. Inside the Node blocks, the following options are recognized:

Host Address

Hostname or address to connect to. Defaults to "localhost".

Port Service

Service name or port number to connect to. Defaults to 2003.

Protocol String

Protocol to use when connecting to Graphite. Defaults to "tcp".

ReconnectInterval Seconds

When set to non-zero, forces the connection to the Graphite backend to be closed and re-opend periodically. This behavior is desirable in environments where the connection to the Graphite backend is done through load balancers, for example. When set to zero, the default, the connetion is kept open for as long as possible.

LogSendErrors false|true

If set to true (the default), logs errors when sending data to Graphite. If set to false, it will not log the errors. This is especially useful when using Protocol UDP since many times we want to use the "fire-and-forget" approach and logging errors fills syslog with unneeded messages.

Prefix String

When UseTags is false, Prefix value is added in front of the host name. When UseTags is true, Prefix value is added in front of series name. Dots and whitespace are not escaped in this string (see EscapeCharacter below).

Postfix String

When UseTags is false, Postfix value appended to the host name. When UseTags is true, Postgix value appended to the end of series name (before the first ; that separates the name from the tags). Dots and whitespace are not escaped in this string (see EscapeCharacter below).

EscapeCharacter Char

Carbon uses the dot (".") as escape character and doesn't allow whitespace in the identifier. The EscapeCharacter option determines which character dots, whitespace and control characters are replaced with. Defaults to underscore ("_").

StoreRates false|true

If set to true (the default), convert counter values to rates. If set to false counter values are stored as is, i. e. as an increasing integer number.

SeparateInstances false|true

If set to true, the plugin instance and type instance will be in their own path component, for example "host.cpu.0.cpu.idle". If set to false (the default), the plugin and plugin instance (and likewise the type and type instance) are put into one component, for example "host.cpu-0.cpu-idle". Option value is not used when UseTags is true.

AlwaysAppendDS false|true

If set to true, append the name of the Data Source (DS) to the "metric" identifier. If set to false (the default), this is only done when there is more than one DS.

PreserveSeparator false|true

If set to false (the default) the "." (dot) character is replaced with EscapeCharacter. Otherwise, if set to true, the "." (dot) character is preserved, i.e. passed through. Option value is not used when UseTags is true.

DropDuplicateFields false|true

If set to true, detect and remove duplicate components in Graphite metric names. For example, the metric name "host.load.load.shortterm" will be shortened to "host.load.shortterm".

UseTags false|true

If set to true, Graphite metric names will be generated as tagged series. This allows for much more flexibility than the traditional hierarchical layout. Example: "test.single;host=example.com;plugin=test;plugin_instance=foo;type=single;type_instance=bar"

You can use Postfix option to add more tags by specifying it like ";tag1=value1;tag2=value2". Note what tagging support was added since Graphite version 1.1.x.

If set to true, the SeparateInstances and PreserveSeparator settings are not used.

Default value: false.

ReverseHost false|true

If set to true, the (dot separated) parts of the host field of the value list will be rewritten in reverse order. The rewrite happens before special characters are replaced with the EscapeCharacter. This option might be convenient if the metrics are presented with Graphite in a DNS like tree structure (probably without replacing dots in hostnames).

Example:

Hostname "node3.cluster1.example.com"

LoadPlugin "cpu"

LoadPlugin "write_graphite"

<Plugin "write_graphite">

<Node "graphite.example.com">

EscapeCharacter "."

ReverseHost true

</Node>

</Plugin>

```
 result on the wire: com.example.cluster1.node3.cpu-0.cpu-idle 99.900993 1543010932

```

Default value: false.

### Plugin "write_log"
The "write_log" plugin writes metrics as INFO log messages.

This plugin supports two output formats: Graphite and JSON.

Synopsis:

```
 <Plugin write_log>
   Format Graphite
 </Plugin>
```

Format Format

The output format to use. Can be one of "Graphite" or "JSON".

### Plugin "write_tsdb"
The "write_tsdb" plugin writes data to OpenTSDB, a scalable open-source time series database. The plugin connects to a TSD, a masterless, no shared state daemon that ingests metrics and stores them in HBase. The plugin uses TCP over the "line based" protocol with a default port 4242. The data will be sent in blocks of at most 1428 bytes to minimize the number of network packets.

Synopsis:

```
 <Plugin write_tsdb>
   ResolveInterval 60
   ResolveJitter 60
   <Node "example">
     Host "tsd-1.my.domain"
     Port "4242"
     HostTags "status=production"
   </Node>
 </Plugin>
```

The configuration consists of one or more <Node Name> blocks and global directives.

Global directives are:

ResolveInterval seconds

ResolveJitter seconds

When collectd connects to a TSDB node, it will request the hostname from DNS. This can become a problem if the TSDB node is unavailable or badly configured because collectd will request DNS in order to reconnect for every metric, which can flood your DNS. So you can cache the last value for ResolveInterval seconds. Defaults to the Interval of the write_tsdb plugin, e.g. 10 seconds. You can also define a jitter, a random interval to wait in addition to ResolveInterval. This prevents all your collectd servers to resolve the hostname at the same time when the connection fails. Defaults to the Interval of the write_tsdb plugin, e.g. 10 seconds.

Note: If the DNS resolution has already been successful when the socket closes, the plugin will try to reconnect immediately with the cached information. DNS is queried only when the socket is closed for a longer than ResolveInterval + ResolveJitter seconds.

Inside the Node blocks, the following options are recognized:

Host Address

Hostname or address to connect to. Defaults to "localhost".

Port Service

Service name or port number to connect to. Defaults to 4242.

HostTags String

When set, HostTags is added to the end of the metric. It is intended to be used for name=value pairs that the TSD will tag the metric with. Dots and whitespace are not escaped in this string.

StoreRates false|true

If set to true, convert counter values to rates. If set to false (the default) counter values are stored as is, as an increasing integer number.

AlwaysAppendDS false|true

If set the true, append the name of the Data Source (DS) to the "metric" identifier. If set to false (the default), this is only done when there is more than one DS.

### Plugin "write_mongodb"
The write_mongodb plugin will send values to MongoDB, a schema-less NoSQL database.

Synopsis:

```
 <Plugin "write_mongodb">
   <Node "default">
     Host "localhost"
     Port "27017"
     Timeout 1000
     StoreRates true
   </Node>
 </Plugin>
```

The plugin can send values to multiple instances of MongoDB by specifying one Node block for each instance. Within the Node blocks, the following options are available:

Host Address

Hostname or address to connect to. Defaults to "localhost".

Port Service

Service name or port number to connect to. Defaults to 27017.

Timeout Milliseconds

Set the timeout for each operation on MongoDB to Timeout milliseconds. Setting this option to zero means no timeout, which is the default.

StoreRates false|true

If set to true (the default), convert counter values to rates. If set to false counter values are stored as is, i.e. as an increasing integer number.

Database Database

User User

Password Password

Sets the information used when authenticating to a MongoDB database. The fields are optional (in which case no authentication is attempted), but if you want to use authentication all three fields must be set.

### Plugin "write_prometheus"
The write_prometheus plugin implements a tiny webserver that can be scraped using Prometheus.

Options:

Host Host

Bind to the hostname / address Host. By default, the plugin will bind to the "any" address, i.e. accept packets sent to any of the hosts addresses. This option is supported only for libmicrohttpd newer than 0.9.0.

Port Port

Port the embedded webserver should listen on. Defaults to 9103.

StalenessDelta Seconds

Time in seconds after which Prometheus considers a metric "stale" if it hasn't seen any update for it. This value must match the setting in Prometheus. It defaults to 300 seconds (5 minutes), same as Prometheus. Background:

Prometheus has a global setting, "StalenessDelta", which controls after which time a metric without updates is considered "stale". This setting effectively puts an upper limit on the interval in which metrics are reported.

When the write_prometheus plugin encounters a metric with an interval exceeding this limit, it will inform you, the user, and provide the metric to Prometheus without a timestamp. That causes Prometheus to consider the metric "fresh" each time it is scraped, with the time of the scrape being considered the time of the update. The result is that there appear more datapoints in Prometheus than were actually created, but at least the metric doesn't disappear periodically.

### Plugin "write_http"
This output plugin submits values to an HTTP server using POST requests and encoding metrics with JSON or using the "PUTVAL" command described in collectd-unixsock(5).

Synopsis:

```
 <Plugin "write_http">
   <Node "example">
     URL "http://example.com/post-collectd"
     User "collectd"
     Password "weCh3ik0"
     Format JSON
   </Node>
 </Plugin>
```

The plugin can send values to multiple HTTP servers by specifying one <Node Name> block for each server. Within each Node block, the following options are available:

URL URL

URL to which the values are submitted to. Mandatory.

User Username

Optional user name needed for authentication.

Password Password

Optional password needed for authentication.

VerifyPeer true|false

Enable or disable peer SSL certificate verification. See <http://curl.haxx.se/docs/sslcerts.html> for details. Enabled by default.

VerifyHost true|false

Enable or disable peer host name verification. If enabled, the plugin checks if the "Common Name" or a "Subject Alternate Name" field of the SSL certificate matches the host name provided by the URL option. If this identity check fails, the connection is aborted. Obviously, only works when connecting to a SSL enabled server. Enabled by default.

CACert File

File that holds one or more SSL certificates. If you want to use HTTPS you will possibly need this option. What CA certificates come bundled with "libcurl" and are checked by default depends on the distribution you use.

CAPath Directory

Directory holding one or more CA certificate files. You can use this if for some reason all the needed CA certificates aren't in the same file and can't be pointed to using the CACert option. Requires "libcurl" to be built against OpenSSL.

ClientKey File

File that holds the private key in PEM format to be used for certificate-based authentication.

ClientCert File

File that holds the SSL certificate to be used for certificate-based authentication.

ClientKeyPass Password

Password required to load the private key in ClientKey.

Header Header

A HTTP header to add to the request. Multiple headers are added if this option is specified more than once. Example:

```
  Header "X-Custom-Header: custom_value"

```

SSLVersion SSLv2|SSLv3|TLSv1|TLSv1_0|TLSv1_1|TLSv1_2

Define which SSL protocol version must be used. By default "libcurl" will attempt to figure out the remote SSL protocol version. See curl_easy_setopt(3) for more details.

Format Command|JSON|KAIROSDB

Format of the output to generate. If set to Command, will create output that is understood by the Exec and UnixSock plugins. When set to JSON, will create output in the JavaScript Object Notation (JSON). When set to KAIROSDB , will create output in the KairosDB format. Defaults to Command.

Attribute String String

Only available for the KAIROSDB output format. Consider the two given strings to be the key and value of an additional tag for each metric being sent out.

You can add multiple Attribute.

TTL Int

Only available for the KAIROSDB output format. Sets the Cassandra ttl for the data points.

Please refer to <http://kairosdb.github.io/docs/build/html/restapi/AddDataPoints.html?highlight=ttl>

Prefix String

Only available for the KAIROSDB output format. Sets the metrics prefix string. Defaults to collectd.

Metrics true|false

Controls whether metrics are POSTed to this location. Defaults to true.

Notifications false|true

Controls whether notifications are POSTed to this location. Defaults to false.

StoreRates true|false

If set to true, convert counter values to rates. If set to false (the default) counter values are stored as is, i.e. as an increasing integer number.

BufferSize Bytes

Sets the send buffer size to Bytes. By increasing this buffer, less HTTP requests will be generated, but more metrics will be batched / metrics are cached for longer before being sent, introducing additional delay until they are available on the server side. Bytes must be at least 1024 and cannot exceed the size of an "int", i.e. 2 GByte. Defaults to 4096.

LowSpeedLimit Bytes per Second

Sets the minimal transfer rate in Bytes per Second below which the connection with the HTTP server will be considered too slow and aborted. All the data submitted over this connection will probably be lost. Defaults to 0, which means no minimum transfer rate is enforced.

Timeout Timeout

Sets the maximum time in milliseconds given for HTTP POST operations to complete. When this limit is reached, the POST operation will be aborted, and all the data in the current send buffer will probably be lost. Defaults to 0, which means the connection never times out.

LogHttpError false|true

Enables printing of HTTP error code to log. Turned off by default.

<Statistics Name>

One Statistics block can be used to specify cURL statistics to be collected for each request to the remote URL. See the section "cURL Statistics" above for details. The "write_http" plugin regularly submits the collected values to the HTTP server. How frequently this happens depends on how much data you are collecting and the size of BufferSize. The optimal value to set Timeout to is slightly below this interval, which you can estimate by monitoring the network traffic between collectd and the HTTP server.

### Plugin "write_influxdb_udp"
The write_influxdb_udp plugin sends data to a instance of InfluxDB using the "Line Protocol". Each plugin is sent as a measurement with a time precision of miliseconds while plugin instance, type and type instance are sent as tags.

```
 <Plugin "write_influxdb_udp">
   Server "influxdb.internal.tld"
   StoreRates "yes"
 </Plugin>
```

<Server Host [Port]>

The Server statement sets the server to send datagrams to. The argument Host may be a hostname, an IPv4 address or an IPv6 address. The optional second argument specifies a port number or a service name. If not given, the default, 8089, is used.

TimeToLive 1-255

Set the time-to-live of sent packets. This applies to all, unicast and multicast, and IPv4 and IPv6 packets. The default is to not change this value. That means that multicast packets will be sent with a TTL of 1 (one) on most operating systems.

MaxPacketSize 1024-65535

Set the maximum size for datagrams received over the network. Packets larger than this will be truncated. Defaults to 1452 bytes, which is the maximum payload size that can be transmitted in one Ethernet frame using IPv6 / UDP.

StoreRates true|false

If set to true, convert absolute, counter and derive values to rates. If set to false (the default) absolute, counter and derive values are sent as is.

### Plugin "write_kafka"
The write_kafka plugin will send values to a Kafka topic, a distributed queue. Synopsis:

```
 <Plugin "write_kafka">
   Property "metadata.broker.list" "broker1:9092,broker2:9092"
   <Topic "collectd">
     Format JSON
   </Topic>
 </Plugin>
```

The following options are understood by the write_kafka plugin:

<Topic Name>

The plugin's configuration consists of one or more Topic blocks. Each block is given a unique Name and specifies one kafka producer. Inside the Topic block, the following per-topic options are understood:

Property String String

Configure the named property for the current topic. Properties are forwarded to the kafka producer library librdkafka.

Key String

Use the specified string as a partitioning key for the topic. Kafka breaks topic into partitions and guarantees that for a given topology, the same consumer will be used for a specific key. The special (case insensitive) string Random can be used to specify that an arbitrary partition should be used.

Format Command|JSON|Graphite

Selects the format in which messages are sent to the broker. If set to Command (the default), values are sent as "PUTVAL" commands which are identical to the syntax used by the Exec and UnixSock plugins. If set to JSON, the values are encoded in the JavaScript Object Notation, an easy and straight forward exchange format.

If set to Graphite, values are encoded in the Graphite format, which is "<metric> <value> <timestamp>\n".

StoreRates true|false

Determines whether or not "COUNTER", "DERIVE" and "ABSOLUTE" data sources are converted to a rate (i.e. a "GAUGE" value). If set to false (the default), no conversion is performed. Otherwise the conversion is performed using the internal value cache. Please note that currently this option is only used if the Format option has been set to JSON.

GraphitePrefix (Format=Graphite only)

A prefix can be added in the metric name when outputting in the Graphite format. When GraphiteUseTags is false, prefix is added before the Host name. Metric name will be "<prefix><host><postfix><plugin><type><name>"

When GraphiteUseTags is true, prefix is added in front of series name.

GraphitePostfix (Format=Graphite only)

A postfix can be added in the metric name when outputting in the Graphite format. When GraphiteUseTags is false, postfix is added after the Host name. Metric name will be "<prefix><host><postfix><plugin><type><name>"

When GraphiteUseTags is true, prefix value appended to the end of series name (before the first ; that separates the name from the tags).

GraphiteEscapeChar (Format=Graphite only)

Specify a character to replace dots (.) in the host part of the metric name. In Graphite metric name, dots are used as separators between different metric parts (host, plugin, type). Default is "_" (Underscore).

GraphiteSeparateInstances false|true

If set to true, the plugin instance and type instance will be in their own path component, for example "host.cpu.0.cpu.idle". If set to false (the default), the plugin and plugin instance (and likewise the type and type instance) are put into one component, for example "host.cpu-0.cpu-idle". Option value is not used when GraphiteUseTags is true.

GraphiteAlwaysAppendDS true|false

If set to true, append the name of the Data Source (DS) to the "metric" identifier. If set to false (the default), this is only done when there is more than one DS.

GraphitePreserveSeparator false|true

If set to false (the default) the "." (dot) character is replaced with GraphiteEscapeChar. Otherwise, if set to true, the "." (dot) character is preserved, i.e. passed through. Option value is not used when GraphiteUseTags is true.

GraphiteUseTags false|true

If set to true Graphite metric names will be generated as tagged series. Default value: false.

StoreRates true|false

If set to true (the default), convert counter values to rates. If set to false counter values are stored as is, i.e. as an increasing integer number. This will be reflected in the "ds_type" tag: If StoreRates is enabled, converted values will have "rate" appended to the data source type, e.g. "ds_type:derive:rate".

Property String String

Configure the kafka producer through properties, you almost always will want to set metadata.broker.list to your Kafka broker list.

### Plugin "write_redis"
The write_redis plugin submits values to Redis, a data structure server.

Synopsis:

```
  <Plugin "write_redis">
    <Node "example">
        Host "localhost"
        Port "6379"
        Timeout 1000
        Prefix "collectd/"
        Database 1
        MaxSetSize -1
        MaxSetDuration -1
        StoreRates true
    </Node>
  </Plugin>
```

Values are submitted to Sorted Sets, using the metric name as the key, and the timestamp as the score. Retrieving a date range can then be done using the "ZRANGEBYSCORE" Redis command. Additionally, all the identifiers of these Sorted Sets are kept in a Set called "collectd/values" (or "${prefix}/values" if the Prefix option was specified) and can be retrieved using the "SMEMBERS" Redis command. You can specify the database to use with the Database parameter (default is 0). See <http://redis.io/commands#sorted_set> and <http://redis.io/commands#set> for details.

The information shown in the synopsis above is the default configuration which is used by the plugin if no configuration is present.

The plugin can send values to multiple instances of Redis by specifying one Node block for each instance. Within the Node blocks, the following options are available:

Node Nodename

The Node block identifies a new Redis node, that is a new Redis instance running on a specified host and port. The node name is a canonical identifier which is used as plugin instance. It is limited to 51 characters in length.

Host Hostname

The Host option is the hostname or IP-address where the Redis instance is running on.

Port Port

The Port option is the TCP port on which the Redis instance accepts connections. Either a service name of a port number may be given. Please note that numerical port numbers must be given as a string, too.

Timeout Milliseconds

The Timeout option sets the socket connection timeout, in milliseconds.

Prefix Prefix

Prefix used when constructing the name of the Sorted Sets and the Set containing all metrics. Defaults to "collectd/", so metrics will have names like "collectd/cpu-0/cpu-user". When setting this to something different, it is recommended but not required to include a trailing slash in Prefix.

Database Index

This index selects the redis database to use for writing operations. Defaults to 0.

MaxSetSize Items

The MaxSetSize option limits the number of items that the Sorted Sets can hold. Negative values for Items sets no limit, which is the default behavior.

MaxSetDuration Seconds

The MaxSetDuration option limits the duration of items that the Sorted Sets can hold. Negative values for Items sets no duration, which is the default behavior.

StoreRates true|false

If set to true (the default), convert counter values to rates. If set to false counter values are stored as is, i.e. as an increasing integer number.

### Plugin "write_riemann"
The write_riemann plugin will send values to Riemann, a powerful stream aggregation and monitoring system. The plugin sends Protobuf encoded data to Riemann using UDP packets.

Synopsis:

```
 <Plugin "write_riemann">
   <Node "example">
     Host "localhost"
     Port "5555"
     Protocol UDP
     StoreRates true
     AlwaysAppendDS false
     TTLFactor 2.0
   </Node>
   Tag "foobar"
   Attribute "foo" "bar"
 </Plugin>
```

The following options are understood by the write_riemann plugin:

<Node Name>

The plugin's configuration consists of one or more Node blocks. Each block is given a unique Name and specifies one connection to an instance of Riemann. Indise the Node block, the following per-connection options are understood:

Host Address

Hostname or address to connect to. Defaults to "localhost".

Port Service

Service name or port number to connect to. Defaults to 5555.

Protocol UDP|TCP|TLS

Specify the protocol to use when communicating with Riemann. Defaults to TCP.

TLSCertFile Path

When using the TLS protocol, path to a PEM certificate to present to remote host.

TLSCAFile Path

When using the TLS protocol, path to a PEM CA certificate to use to validate the remote hosts's identity.

TLSKeyFile Path

When using the TLS protocol, path to a PEM private key associated with the certificate defined by TLSCertFile.

Batch true|false

If set to true and Protocol is set to TCP, events will be batched in memory and flushed at regular intervals or when BatchMaxSize is exceeded. Notifications are not batched and sent as soon as possible.

When enabled, it can occur that events get processed by the Riemann server close to or after their expiration time. Tune the TTLFactor and BatchMaxSize settings according to the amount of values collected, if this is an issue.

Defaults to true

BatchMaxSize size

Maximum payload size for a riemann packet. Defaults to 8192

BatchFlushTimeout seconds

Maximum amount of seconds to wait in between to batch flushes. No timeout by default.

StoreRates true|false

If set to true (the default), convert counter values to rates. If set to false counter values are stored as is, i.e. as an increasing integer number. This will be reflected in the "ds_type" tag: If StoreRates is enabled, converted values will have "rate" appended to the data source type, e.g. "ds_type:derive:rate".

AlwaysAppendDS false|true

If set to true, append the name of the Data Source (DS) to the "service", i.e. the field that, together with the "host" field, uniquely identifies a metric in Riemann. If set to false (the default), this is only done when there is more than one DS.

TTLFactor Factor

Riemann events have a Time to Live (TTL) which specifies how long each event is considered active. collectd populates this field based on the metrics interval setting. This setting controls the factor with which the interval is multiplied to set the TTL. The default value is 2.0. Unless you know exactly what you're doing, you should only increase this setting from its default value.

Notifications false|true

If set to true, create riemann events for notifications. This is true by default. When processing thresholds from write_riemann, it might prove useful to avoid getting notification events.

CheckThresholds false|true

If set to true, attach state to events based on thresholds defined in the Threshold plugin. Defaults to false.

EventServicePrefix String

Add the given string as a prefix to the event service name. If EventServicePrefix not set or set to an empty string (""), no prefix will be used.

Tag String

Add the given string as an additional tag to the metric being sent to Riemann.

Attribute String String

Consider the two given strings to be the key and value of an additional attribute for each metric being sent out to Riemann.

### Plugin "write_sensu"
The write_sensu plugin will send values to Sensu, a powerful stream aggregation and monitoring system. The plugin sends JSON encoded data to a local Sensu client using a TCP socket.

Synopsis:

```
 <Plugin "write_sensu">
   <Node "example">
     Host "localhost"
     Port "3030"
     StoreRates true
     AlwaysAppendDS false
     IncludeSource false
     MetricHandler "influx"
     MetricHandler "default"
     NotificationHandler "flapjack"
     NotificationHandler "howling_monkey"
     Notifications true
   </Node>
   Tag "foobar"
   Attribute "foo" "bar"
 </Plugin>
```

The following options are understood by the write_sensu plugin:

<Node Name>

The plugin's configuration consists of one or more Node blocks. Each block is given a unique Name and specifies one connection to an instance of Sensu. Inside the Node block, the following per-connection options are understood:

Host Address

Hostname or address to connect to. Defaults to "localhost".

Port Service

Service name or port number to connect to. Defaults to 3030.

StoreRates true|false

If set to true (the default), convert counter values to rates. If set to false counter values are stored as is, i.e. as an increasing integer number. This will be reflected in the "collectd_data_source_type" tag: If StoreRates is enabled, converted values will have "rate" appended to the data source type, e.g. "collectd_data_source_type:derive:rate".

AlwaysAppendDS false|true

If set the true, append the name of the Data Source (DS) to the "service", i.e. the field that, together with the "host" field, uniquely identifies a metric in Sensu. If set to false (the default), this is only done when there is more than one DS.

Notifications false|true

If set to true, create Sensu events for notifications. This is false by default. At least one of Notifications or Metrics should be enabled.

Metrics false|true

If set to true, create Sensu events for metrics. This is false by default. At least one of Notifications or Metrics should be enabled.

Separator String

Sets the separator for Sensu metrics name or checks. Defaults to "/".

MetricHandler String

Add a handler that will be set when metrics are sent to Sensu. You can add several of them, one per line. Defaults to no handler.

NotificationHandler String

Add a handler that will be set when notifications are sent to Sensu. You can add several of them, one per line. Defaults to no handler.

EventServicePrefix String

Add the given string as a prefix to the event service name. If EventServicePrefix not set or set to an empty string (""), no prefix will be used.

Tag String

Add the given string as an additional tag to the metric being sent to Sensu.

Attribute String String

Consider the two given strings to be the key and value of an additional attribute for each metric being sent out to Sensu.

IncludeSource false|true

If set to true, then the source host of the metrics/notification is passed on to sensu using the source attribute. This may register the host as a proxy client in sensu. If set to false (the default), then the hostname is discarded, making it appear as if the event originated from the connected sensu agent.

### Plugin "write_stackdriver"
The "write_stackdriver" plugin writes metrics to the Google Stackdriver Monitoring service.

This plugin supports two authentication methods: When configured, credentials are read from the JSON credentials file specified with CredentialFile. Alternatively, when running on Google Compute Engine (GCE), an OAuth token is retrieved from the metadata server and used to authenticate to GCM.

Synopsis:

```
 <Plugin write_stackdriver>
   CredentialFile "/path/to/service_account.json"
   <Resource "global">
     Label "project_id" "monitored_project"
   </Resource>
 </Plugin>
```

CredentialFile file

Path to a JSON credentials file holding the credentials for a GCP service account. If CredentialFile is not specified, the plugin uses Application Default Credentials. That means which credentials are used depends on the environment:

- The environment variable "GOOGLE_APPLICATION_CREDENTIALS" is checked. If this variable is specified it should point to a JSON file that defines the credentials.

- The path "${HOME}/.config/gcloud/application_default_credentials.json" is checked. This where credentials used by the gcloud command line utility are stored. You can use "gcloud auth application-default login" to create these credentials. Please note that these credentials are often of your personal account, not a service account, and are therefore unfit to be used in a production environment.

- When running on GCE, the built-in service account associated with the virtual machine instance is used. See also the Email option below.

Project Project

The Project ID or the Project Number of the Stackdriver Account. The Project ID is a string identifying the GCP project, which you can chose freely when creating a new project. The Project Number is a 12-digit decimal number. You can look up both on the Developer Console. This setting is optional. If not set, the project ID is read from the credentials file or determined from the GCE's metadata service.

Email Email (GCE only)

Choses the GCE Service Account used for authentication. Each GCE instance has a "default" Service Account but may also be associated with additional Service Accounts. This is often used to restrict the permissions of services running on the GCE instance to the required minimum. The write_stackdriver plugin requires the "https://www.googleapis.com/auth/monitoring" scope. When multiple Service Accounts are available, this option selects which one is used by write_stackdriver plugin.

Resource ResourceType

Configures the Monitored Resource to use when storing metrics. More information on Monitored Resources and Monitored Resource Types are available at <https://cloud.google.com/monitoring/api/resources>. This block takes one string argument, the ResourceType. Inside the block are one or more Label options which configure the resource labels.

This block is optional. The default value depends on the runtime environment: on GCE, the "gce_instance" resource type is used, otherwise the "global" resource type ist used:

- On GCE, defaults to the equivalent of this config:

```
  <Resource "gce_instance">
    Label "project_id" "<project_id>"
    Label "instance_id" "<instance_id>"
    Label "zone" "<zone>"
  </Resource>

```

The values for project_id, instance_id and zone are read from the GCE metadata service.

- Elsewhere, i.e. not on GCE, defaults to the equivalent of this config:

```
  <Resource "global">
    Label "project_id" "<Project>"
  </Resource>

```

Where Project refers to the value of the Project option or the project ID inferred from the CredentialFile.

Url Url

URL of the Stackdriver Monitoring API. Defaults to "https://monitoring.googleapis.com/v3".

### Plugin "write_syslog"
The "write_syslog" plugin writes data in syslog format log messages. It implements the basic syslog protocol, RFC 5424, extends it with content-based filtering, rich filtering capabilities, flexible configuration options and adds features such as using TCP for transport. The plugin can connect to a Syslog daemon, like syslog-ng and rsyslog, that will ingest metrics, transform and ship them to the specified output. The plugin uses TCP over the "line based" protocol with a default port 44514. The data will be sent in blocks of at most 1428 bytes to minimize the number of network packets.

Synopsis:

```
 <Plugin write_syslog>
   ResolveInterval 60
   ResolveJitter 60
   <Node "example">
     Host "syslog-1.my.domain"
     Port "44514"
     Prefix "collectd"
     MessageFormat "human"
     HostTags ""
   </Node>
 </Plugin>
```

The configuration consists of one or more <Node Name> blocks and global directives.

Global directives are:

ResolveInterval seconds

ResolveJitter seconds

When collectd connects to a syslog node, it will request the hostname from DNS. This can become a problem if the syslog node is unavailable or badly configured because collectd will request DNS in order to reconnect for every metric, which can flood your DNS. So you can cache the last value for ResolveInterval seconds. Defaults to the Interval of the write_syslog plugin, e.g. 10 seconds. You can also define a jitter, a random interval to wait in addition to ResolveInterval. This prevents all your collectd servers to resolve the hostname at the same time when the connection fails. Defaults to the Interval of the write_syslog plugin, e.g. 10 seconds.

Note: If the DNS resolution has already been successful when the socket closes, the plugin will try to reconnect immediately with the cached information. DNS is queried only when the socket is closed for a longer than ResolveInterval + ResolveJitter seconds.

Inside the Node blocks, the following options are recognized:

Host Address

Hostname or address to connect to. Defaults to "localhost".

Port Service

Service name or port number to connect to. Defaults to 44514.

HostTags String

When set, HostTags is added to the end of the metric. It is intended to be used for adding additional metadata to tag the metric with. Dots and whitespace are not escaped in this string. Examples:

When MessageFormat is set to "human".

```
  ["prefix1" "example1"="example1_v"]["prefix2" "example2"="example2_v"]"

```

When MessageFormat is set to "JSON", text should be in JSON format. Escaping the quotation marks is required.

```
  HostTags "\"prefix1\": {\"example1\":\"example1_v\",\"example2\":\"example2_v\"}"

```

MessageFormat String

MessageFormat selects the format in which messages are sent to the syslog deamon, human or JSON. Defaults to human. Syslog message format:

<priority>VERSION ISOTIMESTAMP HOSTNAME APPLICATION PID MESSAGEID STRUCTURED-DATA MSG

The difference between the message formats are in the STRUCTURED-DATA and MSG parts.

Human format:

```
  <166>1 ISOTIMESTAMP HOSTNAME collectd PID MESSAGEID
  ["collectd" "value": "v1" "plugin"="plugin_v" "plugin_instance"="plugin_instance_v"
  "type_instance"="type_instance_v" "type"="type_v" "ds_name"="ds_name_v" "interval"="interval_v" ]
  "host_tag_example"="host_tag_example_v" plugin_v.type_v.ds_name_v="v1"

```

JSON format:

```
  <166>1 ISOTIMESTAMP HOSTNAME collectd PID MESSAGEID STRUCTURED-DATA
  {
    "collectd": {
    "time": time_as_epoch, "interval": interval_v, "plugin": "plugin_v",
    "plugin_instance": "plugin_instance_v", "type":"type_v",
    "type_instance": "type_instance_v", "plugin_v": {"type_v": v1}
    } , "host":"host_v", "host_tag_example": "host_tag_example_v"
  }

```

StoreRates false|true

If set to true, convert counter values to rates. If set to false (the default) counter values are stored as is, as an increasing integer number.

AlwaysAppendDS false|true

If set to true, append the name of the Data Source (DS) to the "metric" identifier. If set to false (the default), this is only done when there is more than one DS.

Prefix String

When set, Prefix is added to all metrics names as a prefix. It is intended in case you want to be able to define the source of the specific metric. Dots and whitespace are not escaped in this string.

### Plugin "xencpu"
This plugin collects metrics of hardware CPU load for machine running Xen hypervisor. Load is calculated from 'idle time' value, provided by Xen. Result is reported using the "percent" type, for each CPU (core).

This plugin doesn't have any options (yet).

### Plugin "zookeeper"
The zookeeper plugin will collect statistics from a Zookeeper server using the mntr command. It requires Zookeeper 3.4.0+ and access to the client port.

Synopsis:

```
 <Plugin "zookeeper">
   Host "127.0.0.1"
   Port "2181"
 </Plugin>
```

Host Address

Hostname or address to connect to. Defaults to "localhost".

Port Service

Service name or port number to connect to. Defaults to 2181.

## THRESHOLD CONFIGURATION
Starting with version 4.3.0 collectd has support for monitoring. By that we mean that the values are not only stored or sent somewhere, but that they are judged and, if a problem is recognized, acted upon. The only action collectd takes itself is to generate and dispatch a "notification". Plugins can register to receive notifications and perform appropriate further actions.

Since systems and what you expect them to do differ a lot, you can configure thresholds for your values freely. This gives you a lot of flexibility but also a lot of responsibility.

Every time a value is out of range a notification is dispatched. This means that the idle percentage of your CPU needs to be less then the configured threshold only once for a notification to be generated. There's no such thing as a moving average or similar - at least not now.

Also, all values that match a threshold are considered to be relevant or "interesting". As a consequence collectd will issue a notification if they are not received for Timeout iterations. The Timeout configuration option is explained in section "GLOBAL OPTIONS". If, for example, Timeout is set to "2" (the default) and some hosts sends it's CPU statistics to the server every 60 seconds, a notification will be dispatched after about 120 seconds. It may take a little longer because the timeout is checked only once each Interval on the server.

When a value comes within range again or is received after it was missing, an "OKAY-notification" is dispatched.

Here is a configuration example to get you started. Read below for more information.

```
 <Plugin threshold>
   <Type "foo">
     WarningMin    0.00
     WarningMax 1000.00
     FailureMin    0.00
     FailureMax 1200.00
     Invert false
     Instance "bar"
   </Type>
   <Plugin "interface">
     Instance "eth0"
     <Type "if_octets">
       FailureMax 10000000
       DataSource "rx"
     </Type>
   </Plugin>
   <Host "hostname">
     <Type "cpu">
       Instance "idle"
       FailureMin 10
     </Type>
     <Plugin "memory">
       <Type "memory">
         Instance "cached"
         WarningMin 100000000
       </Type>
     </Plugin>
   </Host>
 </Plugin>
```

There are basically two types of configuration statements: The "Host", "Plugin", and "Type" blocks select the value for which a threshold should be configured. The "Plugin" and "Type" blocks may be specified further using the "Instance" option. You can combine the block by nesting the blocks, though they must be nested in the above order, i. e. "Host" may contain either "Plugin" and "Type" blocks, "Plugin" may only contain "Type" blocks and "Type" may not contain other blocks. If multiple blocks apply to the same value the most specific block is used.

The other statements specify the threshold to configure. They must be included in a "Type" block. Currently the following statements are recognized:

FailureMax Value

WarningMax Value

Sets the upper bound of acceptable values. If unset defaults to positive infinity. If a value is greater than FailureMax a FAILURE notification will be created. If the value is greater than WarningMax but less than (or equal to) FailureMax a WARNING notification will be created.

FailureMin Value

WarningMin Value

Sets the lower bound of acceptable values. If unset defaults to negative infinity. If a value is less than FailureMin a FAILURE notification will be created. If the value is less than WarningMin but greater than (or equal to) FailureMin a WARNING notification will be created.

DataSource DSName

Some data sets have more than one "data source". Interesting examples are the "if_octets" data set, which has received ("rx") and sent ("tx") bytes and the "disk_ops" data set, which holds "read" and "write" operations. The system load data set, "load", even has three data sources: "shortterm", "midterm", and "longterm". Normally, all data sources are checked against a configured threshold. If this is undesirable, or if you want to specify different limits for each data source, you can use the DataSource option to have a threshold apply only to one data source.

Invert true|false

If set to true the range of acceptable values is inverted, i. e. values between FailureMin and FailureMax (WarningMin and WarningMax) are not okay. Defaults to false.

Persist true|false

Sets how often notifications are generated. If set to true one notification will be generated for each value that is out of the acceptable range. If set to false (the default) then a notification is only generated if a value is out of range but the previous value was okay. This applies to missing values, too: If set to true a notification about a missing value is generated once every Interval seconds. If set to false only one such notification is generated until the value appears again.

Percentage true|false

If set to true, the minimum and maximum values given are interpreted as percentage value, relative to the other data sources. This is helpful for example for the "df" type, where you may want to issue a warning when less than 5 % of the total space is available. Defaults to false.

Hits Number

Delay creating the notification until the threshold has been passed Number times. When a notification has been generated, or when a subsequent value is inside the threshold, the counter is reset. If, for example, a value is collected once every 10 seconds and Hits is set to 3, a notification will be dispatched at most once every 30 seconds. This is useful when short bursts are not a problem. If, for example, 100% CPU usage for up to a minute is normal (and data is collected every 10 seconds), you could set Hits to 6 to account for this.

Hysteresis Number

When set to non-zero, a hysteresis value is applied when checking minimum and maximum bounds. This is useful for values that increase slowly and fluctuate a bit while doing so. When these values come close to the threshold, they may "flap", i.e. switch between failure / warning case and okay case repeatedly. If, for example, the threshold is configures as

```
  WarningMax 100.0
  Hysteresis 1.0

```

then a Warning notification is created when the value exceeds 101 and the corresponding Okay notification is only created once the value falls below 99, thus avoiding the "flapping".

## FILTER CONFIGURATION
Starting with collectd 4.6 there is a powerful filtering infrastructure implemented in the daemon. The concept has mostly been copied from ip_tables, the packet filter infrastructure for Linux. We'll use a similar terminology, so that users that are familiar with iptables feel right at home.

### Terminology
The following are the terms used in the remainder of the filter configuration documentation. For an ASCII-art schema of the mechanism, see "General structure" below.

Match

A match is a criteria to select specific values. Examples are, of course, the name of the value or it's current value. Matches are implemented in plugins which you have to load prior to using the match. The name of such plugins starts with the "match_" prefix.

Target

A target is some action that is to be performed with data. Such actions could, for example, be to change part of the value's identifier or to ignore the value completely. Some of these targets are built into the daemon, see "Built-in targets" below. Other targets are implemented in plugins which you have to load prior to using the target. The name of such plugins starts with the "target_" prefix.

Rule

The combination of any number of matches and at least one target is called a rule. The target actions will be performed for all values for which all matches apply. If the rule does not have any matches associated with it, the target action will be performed for all values.

Chain

A chain is a list of rules and possibly default targets. The rules are tried in order and if one matches, the associated target will be called. If a value is handled by a rule, it depends on the target whether or not any subsequent rules are considered or if traversal of the chain is aborted, see "Flow control" below. After all rules have been checked, the default targets will be executed.

### General structure
The following shows the resulting structure:

```
 +---------+
 ! Chain   !
 +---------+
      !
      V
 +---------+  +---------+  +---------+  +---------+
 ! Rule    !->! Match   !->! Match   !->! Target  !
 +---------+  +---------+  +---------+  +---------+
      !
      V
 +---------+  +---------+  +---------+
 ! Rule    !->! Target  !->! Target  !
 +---------+  +---------+  +---------+
      !
      V
      :
      :
      !
      V
 +---------+  +---------+  +---------+
 ! Rule    !->! Match   !->! Target  !
 +---------+  +---------+  +---------+
      !
      V
 +---------+
 ! Default !
 ! Target  !
 +---------+
```

### Flow control
There are four ways to control which way a value takes through the filter mechanism:

jump

The built-in jump target can be used to "call" another chain, i. e. process the value with another chain. When the called chain finishes, usually the next target or rule after the jump is executed.

stop

The stop condition, signaled for example by the built-in target stop, causes all processing of the value to be stopped immediately.

return

Causes processing in the current chain to be aborted, but processing of the value generally will continue. This means that if the chain was called via Jump, the next target or rule after the jump will be executed. If the chain was not called by another chain, control will be returned to the daemon and it may pass the value to another chain.

continue

Most targets will signal the continue condition, meaning that processing should continue normally. There is no special built-in target for this condition.

### Synopsis
The configuration reflects this structure directly:

```
 PostCacheChain "PostCache"
 <Chain "PostCache">
   <Rule "ignore_mysql_show">
     <Match "regex">
       Plugin "^mysql$"
       Type "^mysql_command$"
       TypeInstance "^show_"
     </Match>
     <Target "stop">
     </Target>
   </Rule>
   <Target "write">
     Plugin "rrdtool"
   </Target>
 </Chain>
```

The above configuration example will ignore all values where the plugin field is "mysql", the type is "mysql_command" and the type instance begins with "show_". All other values will be sent to the "rrdtool" write plugin via the default target of the chain. Since this chain is run after the value has been added to the cache, the MySQL "show_*" command statistics will be available via the "unixsock" plugin.

### List of configuration options
PreCacheChain ChainName

PostCacheChain ChainName

Configure the name of the "pre-cache chain" and the "post-cache chain". The argument is the name of a chain that should be executed before and/or after the values have been added to the cache. To understand the implications, it's important you know what is going on inside collectd. The following diagram shows how values are passed from the read-plugins to the write-plugins:

```
   +---------------+
   !  Read-Plugin  !
   +-------+-------+
           !
 + - - - - V - - - - +
 : +---------------+ :
 : !   Pre-Cache   ! :
 : !     Chain     ! :
 : +-------+-------+ :
 :         !         :
 :         V         :
 : +-------+-------+ :  +---------------+
 : !     Cache     !--->!  Value Cache  !
 : !     insert    ! :  +---+---+-------+
 : +-------+-------+ :      !   !
 :         !   ,------------'   !
 :         V   V     :          V
 : +-------+---+---+ :  +-------+-------+
 : !  Post-Cache   +--->! Write-Plugins !
 : !     Chain     ! :  +---------------+
 : +---------------+ :
 :                   :
 :  dispatch values  :
 + - - - - - - - - - +

```

After the values are passed from the "read" plugins to the dispatch functions, the pre-cache chain is run first. The values are added to the internal cache afterwards. The post-cache chain is run after the values have been added to the cache. So why is it such a huge deal if chains are run before or after the values have been added to this cache?

Targets that change the identifier of a value list should be executed before the values are added to the cache, so that the name in the cache matches the name that is used in the "write" plugins. The "unixsock" plugin, too, uses this cache to receive a list of all available values. If you change the identifier after the value list has been added to the cache, this may easily lead to confusion, but it's not forbidden of course.

The cache is also used to convert counter values to rates. These rates are, for example, used by the "value" match (see below). If you use the rate stored in the cache before the new value is added, you will use the old, previous rate. Write plugins may use this rate, too, see the "csv" plugin, for example. The "unixsock" plugin uses these rates too, to implement the "GETVAL" command.

Last but not last, the stop target makes a difference: If the pre-cache chain returns the stop condition, the value will not be added to the cache and the post-cache chain will not be run.

Chain Name

Adds a new chain with a certain name. This name can be used to refer to a specific chain, for example to jump to it. Within the Chain block, there can be Rule blocks and Target blocks.

Rule [Name]

Adds a new rule to the current chain. The name of the rule is optional and currently has no meaning for the daemon. Within the Rule block, there may be any number of Match blocks and there must be at least one Target block.

Match Name

Adds a match to a Rule block. The name specifies what kind of match should be performed. Available matches depend on the plugins that have been loaded. The arguments inside the Match block are passed to the plugin implementing the match, so which arguments are valid here depends on the plugin being used. If you do not need any to pass any arguments to a match, you can use the shorter syntax:

```
 Match "foobar"

```

Which is equivalent to:

```
 <Match "foobar">
 </Match>

```

Target Name

Add a target to a rule or a default target to a chain. The name specifies what kind of target is to be added. Which targets are available depends on the plugins being loaded. The arguments inside the Target block are passed to the plugin implementing the target, so which arguments are valid here depends on the plugin being used. If you do not need any to pass any arguments to a target, you can use the shorter syntax:

```
 Target "stop"

```

This is the same as writing:

```
 <Target "stop">
 </Target>

```

### Built-in targets
The following targets are built into the core daemon and therefore need no plugins to be loaded:

return

Signals the "return" condition, see the "Flow control" section above. This causes the current chain to stop processing the value and returns control to the calling chain. The calling chain will continue processing targets and rules just after the jump target (see below). This is very similar to the RETURN target of iptables, see iptables(8). This target does not have any options.

Example:

```
 Target "return"

```

stop

Signals the "stop" condition, see the "Flow control" section above. This causes processing of the value to be aborted immediately. This is similar to the DROP target of iptables, see iptables(8). This target does not have any options.

Example:

```
 Target "stop"

```

write

Sends the value to "write" plugins. Available options:

Plugin Name

Name of the write plugin to which the data should be sent. This option may be given multiple times to send the data to more than one write plugin. If the plugin supports multiple instances, the plugin's instance(s) must also be specified.

If no plugin is explicitly specified, the values will be sent to all available write plugins.

Single-instance plugin example:

```
 <Target "write">
   Plugin "rrdtool"
 </Target>
```

Multi-instance plugin example:

```
 <Plugin "write_graphite">
   <Node "foo">
   ...
   </Node>
   <Node "bar">
   ...
   </Node>
 </Plugin>
  ...
 <Target "write">
   Plugin "write_graphite/foo"
 </Target>
```

jump

Starts processing the rules of another chain, see "Flow control" above. If the end of that chain is reached, or a stop condition is encountered, processing will continue right after the jump target, i. e. with the next target or the next rule. This is similar to the -j command line option of iptables, see iptables(8). Available options:

Chain Name

Jumps to the chain Name. This argument is required and may appear only once.

Example:

```
 <Target "jump">
   Chain "foobar"
 </Target>
```

### Available matches
regex

Matches a value using regular expressions. Available options:

Host Regex

Plugin Regex

PluginInstance Regex

Type Regex

TypeInstance Regex

MetaData String Regex

Match values where the given regular expressions match the various fields of the identifier of a value. If multiple regular expressions are given, all regexen must match for a value to match.

Invert false|true

When set to true, the result of the match is inverted, i.e. all value lists where all regular expressions apply are not matched, all other value lists are matched. Defaults to false.

Example:

```
 <Match "regex">
   Host "customer[0-9]+"
   Plugin "^foobar$"
 </Match>
```

timediff

Matches values that have a time which differs from the time on the server. This match is mainly intended for servers that receive values over the "network" plugin and write them to disk using the "rrdtool" plugin. RRDtool is very sensitive to the timestamp used when updating the RRD files. In particular, the time must be ever increasing. If a misbehaving client sends one packet with a timestamp far in the future, all further packets with a correct time will be ignored because of that one packet. What's worse, such corrupted RRD files are hard to fix.

This match lets one match all values outside a specified time range (relative to the server's time), so you can use the stop target (see below) to ignore the value, for example.

Available options:

Future Seconds

Matches all values that are ahead of the server's time by Seconds or more seconds. Set to zero for no limit. Either Future or Past must be non-zero.

Past Seconds

Matches all values that are behind of the server's time by Seconds or more seconds. Set to zero for no limit. Either Future or Past must be non-zero.

Example:

```
 <Match "timediff">
   Future  300
   Past   3600
 </Match>
```

This example matches all values that are five minutes or more ahead of the server or one hour (or more) lagging behind.

value

Matches the actual value of data sources against given minimum / maximum values. If a data-set consists of more than one data-source, all data-sources must match the specified ranges for a positive match. Available options:

Min Value

Sets the smallest value which still results in a match. If unset, behaves like negative infinity.

Max Value

Sets the largest value which still results in a match. If unset, behaves like positive infinity.

Invert true|false

Inverts the selection. If the Min and Max settings result in a match, no-match is returned and vice versa. Please note that the Invert setting only effects how Min and Max are applied to a specific value. Especially the DataSource and Satisfy settings (see below) are not inverted.

DataSource DSName [DSName ...]

Select one or more of the data sources. If no data source is configured, all data sources will be checked. If the type handled by the match does not have a data source of the specified name(s), this will always result in no match (independent of the Invert setting).

Satisfy Any|All

Specifies how checking with several data sources is performed. If set to Any, the match succeeds if one of the data sources is in the configured range. If set to All the match only succeeds if all data sources are within the configured range. Default is All. Usually All is used for positive matches, Any is used for negative matches. This means that with All you usually check that all values are in a "good" range, while with Any you check if any value is within a "bad" range (or outside the "good" range).

Either Min or Max, but not both, may be unset.

Example:

```
 # Match all values smaller than or equal to 100. Matches only if all data
 # sources are below 100.
 <Match "value">
   Max 100
   Satisfy "All"
 </Match>
 # Match if the value of any data source is outside the range of 0 - 100.
 <Match "value">
   Min   0
   Max 100
   Invert true
   Satisfy "Any"
 </Match>
```

empty_counter

Matches all values with one or more data sources of type COUNTER and where all counter values are zero. These counters usually never increased since they started existing (and are therefore uninteresting), or got reset recently or overflowed and you had really, really bad luck. Please keep in mind that ignoring such counters can result in confusing behavior: Counters which hardly ever increase will be zero for long periods of time. If the counter is reset for some reason (machine or service restarted, usually), the graph will be empty (NAN) for a long time. People may not understand why.

hashed

Calculates a hash value of the host name and matches values according to that hash value. This makes it possible to divide all hosts into groups and match only values that are in a specific group. The intended use is in load balancing, where you want to handle only part of all data and leave the rest for other servers. The hashing function used tries to distribute the hosts evenly. First, it calculates a 32 bit hash value using the characters of the hostname:

```
  hash_value = 0;
  for (i = 0; host[i] != 0; i++)
    hash_value = (hash_value * 251) + host[i];

```

The constant 251 is a prime number which is supposed to make this hash value more random. The code then checks the group for this host according to the Total and Match arguments:

```
  if ((hash_value % Total) == Match)
    matches;
  else
    does not match;

```

Please note that when you set Total to two (i. e. you have only two groups), then the least significant bit of the hash value will be the XOR of all least significant bits in the host name. One consequence is that when you have two hosts, "server0.example.com" and "server1.example.com", where the host name differs in one digit only and the digits differ by one, those hosts will never end up in the same group.

Available options:

Match Match Total

Divide the data into Total groups and match all hosts in group Match as described above. The groups are numbered from zero, i. e. Match must be smaller than Total. Total must be at least one, although only values greater than one really do make any sense. You can repeat this option to match multiple groups, for example:

```
  Match 3 7
  Match 5 7

```

The above config will divide the data into seven groups and match groups three and five. One use would be to keep every value on two hosts so that if one fails the missing data can later be reconstructed from the second host.

Example:

```
 # Operate on the pre-cache chain, so that ignored values are not even in the
 # global cache.
 <Chain "PreCache">
   <Rule>
     <Match "hashed">
       # Divide all received hosts in seven groups and accept all hosts in
       # group three.
       Match 3 7
     </Match>
     # If matched: Return and continue.
     Target "return"
   </Rule>
   # If not matched: Return and stop.
   Target "stop"
 </Chain>
```

### Available targets
notification

Creates and dispatches a notification. Available options:

Message String

This required option sets the message of the notification. The following placeholders will be replaced by an appropriate value:

%{host}

%{plugin}

%{plugin_instance}

%{type}

%{type_instance}

These placeholders are replaced by the identifier field of the same name.

%{ds:name}

These placeholders are replaced by a (hopefully) human readable representation of the current rate of this data source. If you changed the instance name (using the set or replace targets, see below), it may not be possible to convert counter values to rates.

Please note that these placeholders are case sensitive!

Severity "FAILURE"|"WARNING"|"OKAY"

Sets the severity of the message. If omitted, the severity "WARNING" is used.

Example:

```
  <Target "notification">
    Message "Oops, the %{type_instance} temperature is currently %{ds:value}!"
    Severity "WARNING"
  </Target>
```

replace

Replaces parts of the identifier using regular expressions. Available options:

Host Regex Replacement

Plugin Regex Replacement

PluginInstance Regex Replacement

TypeInstance Regex Replacement

MetaData String Regex Replacement

DeleteMetaData String Regex

Match the appropriate field with the given regular expression Regex. If the regular expression matches, that part that matches is replaced with Replacement. If multiple places of the input buffer match a given regular expression, only the first occurrence will be replaced. You can specify each option multiple times to use multiple regular expressions one after another.

Example:

```
 <Target "replace">
   # Replace "example.net" with "example.com"
   Host "\\<example.net\\>" "example.com"
   # Strip "www." from hostnames
   Host "\\<www\\." ""
 </Target>
```

set

Sets part of the identifier of a value to a given string. Available options:

Host String

Plugin String

PluginInstance String

TypeInstance String

MetaData String String

Set the appropriate field to the given string. The strings for plugin instance, type instance, and meta data may be empty, the strings for host and plugin may not be empty. It's currently not possible to set the type of a value this way. The following placeholders will be replaced by an appropriate value:

%{host}

%{plugin}

%{plugin_instance}

%{type}

%{type_instance}

These placeholders are replaced by the identifier field of the same name.

%{meta:name}

These placeholders are replaced by the meta data value with the given name.

Please note that these placeholders are case sensitive!

DeleteMetaData String

Delete the named meta data field.

Example:

```
 <Target "set">
   PluginInstance "coretemp"
   TypeInstance "core3"
 </Target>
```

### Backwards compatibility
If you use collectd with an old configuration, i. e. one without a Chain block, it will behave as it used to. This is equivalent to the following configuration:

```
 <Chain "PostCache">
   Target "write"
 </Chain>
```

If you specify a PostCacheChain, the write target will not be added anywhere and you will have to make sure that it is called where appropriate. We suggest to add the above snippet as default target to your "PostCache" chain.

### Examples
Ignore all values, where the hostname does not contain a dot, i. e. can't be an FQDN.

```
 <Chain "PreCache">
   <Rule "no_fqdn">
     <Match "regex">
       Host "^[^\.]*$"
     </Match>
     Target "stop"
   </Rule>
   Target "write"
 </Chain>
```

## IGNORELISTS
Ignorelists are a generic framework to either ignore some metrics or report specific metrics only. Plugins usually provide one or more options to specify the items (mounts points, devices, ...) and the boolean option "IgnoreSelected".

Select String

Selects the item String. This option often has a plugin specific name, e.g. Sensor in the "sensors" plugin. It is also plugin specific what this string is compared to. For example, the "df" plugin's MountPoint compares it to a mount point and the "sensors" plugin's Sensor compares it to a sensor name. By default, this option is doing a case-sensitive full-string match. The following config will match "foo", but not "Foo":

```
  Select "foo"

```

If String starts and ends with "/" (a slash), the string is compiled as a regular expression. For example, so match all item starting with "foo", use could use the following syntax:

```
  Select "/^foo/"

```

The regular expression is not anchored, i.e. the following config will match "foobar", "barfoo" and "AfooZ":

```
  Select "/foo/"

```

The Select option may be repeated to select multiple items.

IgnoreSelected true|false

If set to true, matching metrics are ignored and all other metrics are collected. If set to false, matching metrics are collected and all other metrics are ignored.

## SEE ALSO
collectd(1), collectd-exec(5), collectd-perl(5), collectd-unixsock(5), types.db(5), hddtemp(8), iptables(8), kstat(3KSTAT), mbmon(1), psql(1), regex(7), rrdtool(1), sensors(1)

## AUTHOR
Florian Forster <octo@collectd.org>